The IRS publishes migration data for the US population based upon the individual tax returns filed with the IRS, where they track on a year-by-year basis

• where people were coming from - the prior state of residency
• where people moving to - the new state of residency
• number of returns filed - approximate number of households that migrated
• number of exemptions - approximate number of individuals
• the adjusted gross income (AGI) - recorded in thousands of dollars

The raw data published on the IRS website clearly shows patterns of evolution - changing patterns of what is recorded, how it is record, and naming conventions used - making it a challenge to track changes in the underlying data over time. The current dataset attempts to address these shortcomings by normalizing the record layout, standardizing the conventions, and collecting the annual into a single, coherent dataset.

An individual record is laid out with 9 fields

Y1 Y1_STATE_FIPS Y1_STATE_ABBR Y1_STATE_NAME Y2 Y2_STATE_FIPS Y2_STATE_ABBR Y2_STATE_NAME NUM_RETURNS NUM_EXEMPTIONS AGI Here, Y1 refers to the first year (from where the people are migrating) while Y2 refers to the second year (to where the people are migrating). As this is annual data, Y2 should always be the next year after Y1. Associated with each year are three different ways of identifying a state - the name of the state, it's two-letter abbreviaion, and it's FIPS code. Granted, carrying around three IDs per state is redundant; however, the various IDs are useful in different contexts. One thing to note - the IRS data represents migration into and out of the country via the introduction of a fake state, identified by STATE_NAME=FOREIGN, STATE_ABBR=FR, and STATE_FIPS=57.

From any given state, the dataset records migration to 52 destinations

• either not moving, or staying in the same state
• migrating to one of the other 49 states
• migrating to Washington DC
• migrating overseas (i.e., to the FOREIGN state)

Similarly, the dataset represents the migation into any given state as being from one of 52 destinations. Typically, the numbers associated with "staying put" constitute, by far, the largest contingent of tax payers for the given state. The one exception to this description is the FOREIGN state. The dataset does not record "staying put" outside of the country; there is no record for FOREIGN-to-FOREIGN migration. As such, there are 51, not 52, destinations paired with migration to-and-from the FOREIGN state.

This study contains county-level net migration estimates, by five-year age cohorts, sex, race, and Hispanic origin, for the intercensal period from 2010 to 2020. This file is part of a series of estimates done for each decade since 1950. Details on how net migration and corresponding net migration rates are calculated are described in the methodology document. In addition, data is available through mapping and charting interfaces at Net Migration Patterns for U.S. Counties.

Migration Dataset- Exploratory Data Analysis This project explores global migration trends using data extracted from UN migration–related sources. The analysis includes data cleaning, handling missing values, detecting outliers, generating descriptive statistics, and creating visualizations aimed at understanding worldwide refugee and migration patterns.

  Dataset Summary

-Source: Kaggle (uploaded by M P Ajith Bharadwaj) -Time period: 1950-2020-Features: 16 numeric + 1 categorical… See the full description on the dataset page: https://huggingface.co/datasets/Mayab2/migration.

In the past four centuries, the population of the Thirteen Colonies and United States of America has grown from a recorded 350 people around the Jamestown colony in Virginia in 1610, to an estimated 346 million in 2025. While the fertility rate has now dropped well below replacement level, and the population is on track to go into a natural decline in the 2040s, projected high net immigration rates mean the population will continue growing well into the next century, crossing the 400 million mark in the 2070s. Indigenous population Early population figures for the Thirteen Colonies and United States come with certain caveats. Official records excluded the indigenous population, and they generally remained excluded until the late 1800s. In 1500, in the first decade of European colonization of the Americas, the native population living within the modern U.S. borders was believed to be around 1.9 million people. The spread of Old World diseases, such as smallpox, measles, and influenza, to biologically defenseless populations in the New World then wreaked havoc across the continent, often wiping out large portions of the population in areas that had not yet made contact with Europeans. By the time of Jamestown's founding in 1607, it is believed the native population within current U.S. borders had dropped by almost 60 percent. As the U.S. expanded, indigenous populations were largely still excluded from population figures as they were driven westward, however taxpaying Natives were included in the census from 1870 to 1890, before all were included thereafter. It should be noted that estimates for indigenous populations in the Americas vary significantly by source and time period. Migration and expansion fuels population growth The arrival of European settlers and African slaves was the key driver of population growth in North America in the 17th century. Settlers from Britain were the dominant group in the Thirteen Colonies, before settlers from elsewhere in Europe, particularly Germany and Ireland, made a large impact in the mid-19th century. By the end of the 19th century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. It is also estimated that almost 400,000 African slaves were transported directly across the Atlantic to mainland North America between 1500 and 1866 (although the importation of slaves was abolished in 1808). Blacks made up a much larger share of the population before slavery's abolition. Twentieth and twenty-first century The U.S. population has grown steadily since 1900, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. Since WWII, the U.S. has established itself as the world's foremost superpower, with the world's largest economy, and most powerful military. This growth in prosperity has been accompanied by increases in living standards, particularly through medical advances, infrastructure improvements, clean water accessibility. These have all contributed to higher infant and child survival rates, as well as an increase in life expectancy (doubling from roughly 40 to 80 years in the past 150 years), which have also played a large part in population growth. As fertility rates decline and increases in life expectancy slows, migration remains the largest factor in population growth. Since the 1960s, Latin America has now become the most common origin for migrants in the U.S., while immigration rates from Asia have also increased significantly. It remains to be seen how immigration restrictions of the current administration affect long-term population projections for the United States.

The Population Projections for the State of Tennessee, produced for the Tennessee State Data Center, contain projections for each county in Tennessee by race, age, and sex for each year from 2020 to 2070. Age is defined by five-year bands, starting with an “age 0-4” group and ending with an “age 85+” group. Race is delineated as one of four categories that combine race and ethnic definitions:White Non-HispanicBlack Non-HispanicAll HispanicOther non-Hispanic, including two or more races. Our forecast implements a cohort-component methodology. We specify the base year as 2000 and the launch year as 2021. Thus, we inform the forecast with trends from 2000 to 2020. Using vital statistics data from the Tennessee Department of Health, we project the population change resulting from natural components (births minus deaths). Differences between actual population values as reported by the Census and values predicted using births and deaths are used to establish net migration patterns. The forecast used these predicted net migration patterns; life tables from the Social Security Administration; recent average birth rates by county, race, and age of female; and forecast future U.S. populations.The 2020 base year population estimates for Tennessee Counties are from the 2020 Vintage Estimates of Population and Housing Units produced by the US Census Bureau.

DEC. 22, 2022 – After a historically low rate of change between 2020 and 2021, the U.S. resident population increased by 0.4%, or 1,256,003, to 333,287,557 in 2022, according to the U.S. Census Bureau’s Vintage 2022 national and state population estimates and components of change released today.

Net international migration — the number of people moving in and out of the country — added 1,010,923 people between 2021 and 2022 and was the primary driver of growth. This represents 168.8% growth over 2021 totals of 376,029 – an indication that migration patterns are returning to pre-pandemic levels. Positive natural change (births minus deaths) increased the population by 245,080.

“There was a sizeable uptick in population growth last year compared to the prior year’s historically low increase,” said Kristie Wilder, a demographer in the Population Division at the Census Bureau. “A rebound in net international migration, coupled with the largest year-over-year increase in total births since 2007, is behind this increase.”

Regional Patterns The South, the most populous region with a resident population of 128,716,192, was the fastest-growing and the largest-gaining region last year, increasing by 1.1%, or 1,370,163. Positive net domestic migration (867,935) and net international migration (414,740) were the components with the largest contributions to this growth, adding a combined 1,282,675 residents.

The West was the only other region to experience growth in 2022, having gained 153,601 residents — an annual increase of 0.2% for a total resident population of 78,743,364 — despite losing 233,150 residents via net domestic migration (the difference between residents moving in and out of an area). Natural increase (154,405) largely accounted for the growth in the West.

The Northeast, with a population of 57,040,406, and the Midwest, with a population of 68,787,595, lost 218,851 (-0.4%) and 48,910 (-0.1%) residents, respectively. The declines in these regions were due to negative net domestic migration.

Changes in State Population Increasing by 470,708 people since July 2021, Texas was the largest-gaining state in the nation, reaching a total population of 30,029,572. By crossing the 30-million-population threshold this past year, Texas joins California as the only states with a resident population above 30 million. Growth in Texas last year was fueled by gains from all three components: net domestic migration (230,961), net international migration (118,614), and natural increase (118,159).

Florida was the fastest-growing state in 2022, with an annual population increase of 1.9%, resulting in a total resident population of 22,244,823.

“While Florida has often been among the largest-gaining states,” Wilder noted, “this was the first time since 1957 that Florida has been the state with the largest percent increase in population.”

It was also the second largest-gaining state behind Texas, with an increase of 416,754 residents. Net migration was the largest contributing component of change to Florida’s growth, adding 444,484 residents. New York had the largest annual numeric and percent population decline, decreasing by 180,341 (-0.9%). Net domestic migration (-299,557) was the largest contributing component to the state’s population decline.

Eighteen states experienced a population decline in 2022, compared to 15 and DC the prior year. California, with a population of 39,029,342, and Illinois, with a population of 12,582,032, also had six-figure decreases in resident population. Both states’ declining populations were largely due to net domestic outmigration, totaling 343,230 and 141,656, respectively.

Puerto Rico Population Changes In 2022, Puerto Rico’s population was 3,221,789. This reflects a decrease of 1.3%, or 40,904 people, between 2021 and 2022.

Puerto Rico’s population decline resulted from negative net international migration (-26,447) and negative natural change (-14,457), where deaths outnumber births.

                            **###Components of Change for States**

In 2022, 24 states experienced negative natural change, or natural decrease. Florida had the highest natural decrease at -40,216, followed by Pennsylvania (-23,021) and Ohio (-19,543). In 2021, 25 states had natural decrease.

Of the 26 states and the District of Columbia where births outnumbered deaths, Texas (118,159), California (106,155) and New York (35,611) had the highest natural increase.

All 50 states and the District of Columbia saw positive net international migration with California (125,715), Florida (125,629) and Texas (118,614) having the largest gains.

The biggest gains from net domestic migration last year were in Florida (318,855), Texas (230,961) and North Carolina (99,796), while the biggest losses were in California (-343,230), New York (-299,557) and Illinois...

The project leads for the collection of this data were Erin Zulliger and Richard Shinn. The winter range of the West Goose Lake Rocky Mountain elk (Cervus canadensis nelsoni) sub-herd is located north of Alturas and west of Highway 395 within the Devil’s Garden Ranger District of the Modoc National Forest. This area is characterized by juniper (Juniperus occidentalis) woodlands, and sagebrush flats with some stands of lodgepole (Pinus contorta) and ponderosa pine (Pinus ponderosa) throughout flat, rocky terrain. From this area, a portion of the herd migrates approximately 50 miles north into Oregon’s Fremont National Forest, habitat that primarily consists of lodgepole and ponderosa pine forests. Minimal barriers exist along this migration route since the corridor primarily occurs on land managed by the US Forest Service. Additionally, although the core migration route does cross Highway 140, little to no impacts are known to exist from this crossing. Elk (12 adult females, 1 adult male, and 3 juvenile [less than 1 year of age] males) were captured from 2018 to February 2020 and equipped with Lotek and Vectronic satellite GPS collars. Additional GPS data was collected from elk (2 females and 1 male) in 1999-2002 and included in the analysis to supplement the small sample size of the 2018-2020 dataset. GPS locations were fixed at 4-hour intervals in the 2018-2020 dataset and 6 to 8-hour intervals in the 1999-2002 dataset. To improve the quality of the data set as per Bjørneraas et al. (2010), the GPS data were filtered prior to analysis to remove locations which were: i) further from either the previous point or subsequent point than an individual elk is able to travel in the elapsed time, ii) forming spikes in the movement trajectory based on outgoing and incoming speeds and turning angles sharper than a predefined threshold , or iii) fixed in 2D space and visually assessed as a bad fix by the analyst. The methodology used for this migration analysis allowed for the mapping of winter ranges and the identification and prioritization of migration corridors. Brownian Bridge Movement Models (BBMMs; Sawyer et al. 2009) were constructed with GPS collar data from 12 migrating elk, including 25 migration sequences, location, date, time, and average location error as inputs in Migration Mapper. Five migration sequences from 3 elk, with an average migration time of 6.8 days and an average migration distance of 16.14 km, were used from the 1999-2002 dataset. All three of these elk were used to supplement the eastern members of this herd, which travel shorter distances between summer and winter range than western individuals in the sample. Twenty migration sequences from 9 elk, with an average migration time of 11.2 days and an average migration distance of 57.75 km, were used from the 2018-2020 dataset. Corridors and stopovers were prioritized based on the number of animals moving through a particular area. BBMMs were produced at a spatial resolution of 50 m using a sequential fix interval of less than 27 hours and a fixed motion variance of 1400. Winter range analyses were based on data from 11 individual elk and 18 wintering sequences using a fixed motion variance of 1400. Winter range designations for this herd would likely expand with a larger sample, filling in some of the gaps between winter range polygons in the map. Large water bodies were clipped from the final outputs.Corridors are visualized based on elk use per cell, with greater than or equal to 1 elk and greater than or equal to 3 elk (20% of the sample) representing migration corridors and high use corridors, respectively. Stopovers were calculated as the top 10 percent of the population level utilization distribution during migrations and can be interpreted as high use areas. Stopover polygon areas less than 20,000 m2were removed, but remaining small stopovers may be interpreted as short-term resting sites, likely based on a small concentration of points from an individual animal. Winter range is visualized as the 50thpercentile contour of the winter range utilization distribution.

The Wenatchee Mountains mule deer herd inhabits a matrix of private and public lands along the eastern slope of the Cascade Range in Chelan and Kittitas Counties in Washington (fig. 24). Historically, the Wenatchee Mountains mule deer herd was separated into two subherds, Chelan and Kittitas; however, recent GPS collar data indicated the mule deer south of U.S. Highway 2 and north of Interstate 90 represent one population. Their high-use winter range extends along the foothills west and south of Wenatchee, Washington and throughout the foothills of the Kittitas Valley near Ellensburg. Their low-use winter range occurs along the foothills west of the Columbia River north of Interstate 90. In the spring, migratory individuals travel west into the Wenatchee Mountains to their summer range, which includes regional wilderness areas. Between 2020 and 2021, collaring efforts focused on the foothills near Wenatchee and in the surrounding foothills near Ellensburg. Collar data analysis indicated the Wenatchee Mountains mule deer population is partially migratory. A high proportion of migratory individuals inhabit the northern winter range of the Wenatchee Mountains, and resident individuals more commonly inhabit the foothills of the Kittitas Valley. In 2022, collaring efforts of mule deer (n=25) in the northern winter range foothills near Wenatchee targeted the higher proportion of the migratory population, to more clearly identify the movement corridors intersecting U.S. Highway 97 near Blewett Pass. The herd has several challenges, including the increasing frequency of large-scale wildfires and residential developments, which continue to degrade and reduce available winter habitat. Disturbance from human recreation on the winter range continues to be a concern. Additionally, U.S. Highway 97 and State Route 970 receive high volumes of traffic in the region and present semipermeable barriers to spring and fall migration. These mapping layers show the location of the migration routes for mule deer (Odocoileus hemionus) in the Wenatchee population in Washington. They were developed from 184 migration sequences collected from a sample size of 59 animals comprising GPS locations collected every 4 hours.

In 2024, when asked how undocumented immigrants to the United States should be handled, 39 percent of American survey respondents said that there should be a way for them to become legal U.S. residents and apply for citizenship. In 2022, it was estimated that there were about eleven million undocumented immigrants in the United States.

As of 2023, 27.3 percent of California's population were born in a country other than the United States. New Jersey, New York, Florida, and Nevada rounded out the top five states with the largest population of foreign born residents in that year. For the country as a whole, 14.3 percent of residents were foreign born.

The Likely Tables herd contains migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Instead, much of the herd displays a nomadic tendency, slowly migrating north for the summer using various high use areas as they move. Therefore, annual ranges were modeled using year-round data to demarcate high use areas in lieu modeling specific winter ranges. A high use area being used during winter by many of the collared animals is west of the Warner Mountains, east of U.S. Highway 395, and north of Moon Lake. Some animals live in the agricultural fields west of U.S. Highway 395. There appears to be little if any movement across the highway, which is fenced on both sides in this area. Summer ranges are spread out, with some individuals moving as far north as Goose Lake. A few outliers in the herd moved long distances south toward the Lassen herd or east to Nevada. Drought, increasing fire frequency, invasive annual grasses, and juniper encroachment negatively affect pronghorn habitat. Recent population surveys indicate a declining population (Trausch and others, 2020). Juniper removal on public and private lands have potential to improve habitat quality and potentially reduce predation (Ewanyk, 2020). Fences on public and private lands affect movement corridors and increase crossing and/or migration times. Recent fence modifications on BLM lands have shown potential to ease pronghorn movements (Hudgens, 2022). These mapping layers show the location of the migration routes for pronghorn (Antilocapra americana) in the Likely Tables population in California. They were developed from 29 migration sequences collected from a sample size of 17 animals comprising GPS locations collected every 1-4 hours.

Growing evidence supports the hypothesis that temperate herbivores surf the green wave of emerging plants during spring migration. Despite the importance of autumn migration, few studies have conceptualized resource tracking of temperate herbivores during this critical season. We adapted the Frost Wave Hypothesis (FWH), which posits that animals pace their autumn migration to reduce exposure to snow but increase acquisition of forage. We tested the FWH in a population of mule deer in Wyoming, USA by tracking the autumn migrations of n = 163 mule deer that moved 15–288 km from summer to winter range. Migrating deer experienced similar amounts of snow but 1.4–2.1 times more residual forage than if they had naïve knowledge of when or how fast to migrate. Importantly, deer balanced exposure to snow and forage in a spatial manner. At the fine scale, deer avoided snow near their mountainous summer ranges and became more risk-prone to snow near winter range. Aligning with their higher tolerance of snow and lingering behavior to acquire residual forage, deer increased stopover use by 1 ± 1 day (95% CI) day for every 10% of their migration completed. Our findings support the prediction that mule deer pace their autumn migration with the onset of snow and residual forage but refine the FWH to include movement behavior en route that is spatially dynamic. Methods Animal capture and handling From 2014–2020, we captured n = 220 adult female mule deer (>1-yr-old) in the Red Desert via helicopter net-gunning (LaSharr et al., 2022). We outfitted all deer with store-on-board or iridium GPS collars that collected locations every 1–2 hours (Advanced Telemetry Systems, Inc., Isanti, MN, USA; LOTEK Wireless Inc., New Market, Ontario, CAN; Telonics Inc, Mesa, AZ, USA). We used GPS data from a previous study on the Sublette Herd (2011–2013; Sawyer et al., 2016) to analyze movement for an additional n = 27 adult female mule deer (< 1 yr old; n = 66 animal-years) which were outfitted with store-on-board GPS collars that collected locations every 3 hours (Telonics, Mesa, AZ, USA). All animal capture and handling protocols were approved by the Wyoming Game and Fish Department (Chapter 33-937) and an Institutional Animal Care and Use Committee at the University of Wyoming (Protocol 20131111KM00040, 20151204KM00135, 20170215KM00260, 20200302MK00411). Classification of migratory tactics and delineation of seasonal ranges We used net squared displacement (Bunnefeld et al., 2011) to determine start and end dates of migration, delineate migratory routes, and calculate net displacement between each GPS location and the start location of autumn migration. We used 95% kernel utilization distributions (Worton, 1989) to delineate summer ranges (end of spring migration–start of autumn migration). Following methods from Sawyer et al. (2016), we classified migratory tactics based on migration distance and where deer spent summer. Movement rate and stopover use For each animal-year, we divided migration distance (km; Euclidean distance between first and last locations of autumn migration) by duration to determine hourly and daily rates of movement. We used a 10% utilization distribution from a Brownian bridge movement model (Horne et al., 2007) to delineate high-use stopovers (≥ 3 days of use; Rodgers et al., 2021). Because some animals moved back and forth between adjacent stopovers, we aggregated stopovers that were within a 5-km radius to reduce probability of overestimating stopover use. References

Bunnefeld, N., L. Börger, B. van Moorter, C. M. Rolandsen, H. Dettki, E. J. Solberg, and G. Ericsson. 2011. “A model-driven approach to quantify migration patterns: individual, regional and yearly differences.” Journal of Animal Ecology 80: 466–476. Horne, J. S., E. O. Garton, S. M. Krone, and J. S. Lewis. 2007. “Analyzing animal movements using Brownian bridges.” Ecology 88: 2354–2363. LaSharr, T. N., S. P. H. Dwinnell, B. L. Wagler, H. Sawyer, R. P. Jakopak, A. C. Ortega, L. Wilde, M. J. Kauffman, K. S. Huggler, P. W. Burke, M. Valdez, P. Lionberger, D. G. Brimeyer, B. Scurlock, J. Randall, R. C. Kaiser, M. Thonhoff, G. L. Fralick, and K. L. Monteith. 2022. “Evaluating risks associated with capture and handling of mule deer for individual-based, long-term research.” Journal of Wildlife Management 87: https://doi.org/10.1002/jwmg.22333. Rodgers, P. A., H. Sawyer, T. W. Mong, S. Stephens, and M. J. Kauffman. 2021. “Sex-specific migratory behaviors in a temperate ungulate.” Ecosphere 12: https://doi.org/10.1002/ecs2.3424. Sawyer, H., A. D. Middleton, M. M. Hayes, M. J. Kauffman, and K. L. Monteith. 2016. “The extra mile: ungulate migration distance alters the use of seasonal range and exposure to anthropogenic risk.” Ecosphere 7: https://doi.org/10.1002/ecs2.1534. Worton, B. J. 1989. “Kernel methods for estimating the utilization distribution in home-range studies.” Ecology 70: 164–168.

Population dynamics, its types. Population migration (external, internal), factors determining it, main trends. Impact of migration on population health.

Under the guidance of Moldoev M.I. Sir By Riya Patil and Rutuja Sonar

Abstract

Population dynamics influence development and vice versa, at various scale levels: global, continental/world-regional, national, regional, and local. Debates on how population growth affects development and how development affects population growth have already been subject of intensive debate and controversy since the late 18th century, and this debate is still ongoing. While these two debates initially focused mainly on natural population growth, the impact of migration on both population dynamics and development is also increasingly recognized. While world population will continue growing throughout the 21st century, there are substantial and growing contrasts between and within world-regions in the pace and nature of that growth, including some countries where population is stagnating or even shrinking. Because of these growing contrasts, population dynamics and their interrelationships with development have quite different governance implications in different parts of the world.

1. Population Dynamics

Population dynamics refers to the changes in population size, structure, and distribution over time. These changes are influenced by four main processes:

Birth rate (natality)

Death rate (mortality)

Immigration (inflow of people)

Emigration (outflow of people)

Types of Population Dynamics

Natural population change: Based on birth and death rates.

Migration-based change: Caused by people moving in or out of a region.

Demographic transition: A model that explains changes in population growth as societies industrialize.

Population distribution: Changes in where people live (urban vs rural).

2. Population Migration

Migration refers to the movement of people from one location to another, often across political or geographical boundaries.

Types of Migration

External migration (international):

Movement between countries.

Examples: Refugee relocation, labor migration, education.

Internal migration:

Movement within the same country or region.

Examples: Rural-to-urban migration, inter-state migration.

3. Factors Determining Migration

Migration is influenced by push and pull factors:

Push factors (reasons to leave a place):

Unemployment

Conflict or war

Natural disasters

Poverty

Lack of services or opportunities

Pull factors (reasons to move to a place):

Better job prospects

Safety and security

Higher standard of living

Education and healthcare access

Family reunification

4. Main Trends in Migration

Urbanization: Mass movement to cities for work and better services.

Global labor migration: Movement from developing to developed countries.

Refugee and asylum seeker flows: Due to conflict or persecution.

Circular migration: Repeated movement between two or more locations.

Brain drain/gain: Movement of skilled labor away from (or toward) a country.

5. Impact of Migration on Population Health

Positive Impacts:

Access to better healthcare (for migrants moving to better systems).

Skills and knowledge exchange among health professionals.

Remittances improving healthcare affordability in home countries.

Negative Impacts:

Migrants’ health risks: Increased exposure to stress, poor living conditions, and occupational hazards.

Spread of infectious diseases: Especially when health screening is lacking.

Strain on health services: In receiving areas, especially with sudden or large influxes.

Mental health challenges: Due to cultural dislocation, discrimination, or trauma.

Population dynamics is one of the fundamental areas of ecology, forming both the basis for the study of more complex communities and of many applied questions. Understanding population dynamics is the key to understanding the relative importance of competition for resources and predation in structuring ecological communities, which is a central question in ecology.

Population dynamics plays a central role in many approaches to preserving biodiversity, which until now have been primarily focused on a single species approach. The calculation of the intrinsic growth rate of a species from a life table is often the central piece of conservation plans. Similarly, management of natural resources, such as fisheries, depends on population dynamics as a way to determine appropriate management actions.

Population dynamics can be characterized by a nonlinear system of difference or differential equations between the birth sizes of consecutive periods. In such a nonlinear system, when the feedback elasticity of previous events on current birth size is larger, the more likely the dynamics will be volatile. Depending on the classification criteria of the population, the revealed cyclical behavior has various interpretations. Under different contextual scenarios, Malthusian cycles, Easterlin cycles, predator–prey cycles, dynastic cycles, and capitalist–laborer cycles have been introduced and analyzed

Generally, population dynamics is a nonlinear stochastic process. Nonlinearities tend to be complicated to deal with, both when we want to do analytic stochastic modelling and when analysing data. The way around the problem is to approximate the nonlinear model with a linear one, for which the mathematical and statistical theories are more developed and tractable. Let us assume that the population process is described as:

(1)Nt=f(Nt−1,εt)

where Nt is population density at time t and εt is a series of random variables with identical distributions (mean and variance). Function f specifies how the population density one time step back, plus the stochastic environment εt, is mapped into the current time step. Let us assume that the (deterministic) stationary (equilibrium) value of the population is N* and that ε has mean ε*. The linear approximation of Eq. (1) close to N* is then:

(2)xt=axt−1+bϕt

where xt=Nt−N*, a=f

f(N*,ε*)/f

N, b=ff(N*,ε*)/fε, and ϕt=εt−ε*

The term population refers to the members of a single species that can interact with each other. Thus, the fish in a lake, or the moose on an island, are clear examples of a population. In other cases, such as trees in a forest, it may not be nearly so clear what a population is, but the concept of population is still very useful.

Population dynamics is essentially the study of the changes in the numbers through time of a single species. This is clearly a case where a quantitative description is essential, since the numbers of individuals in the population will be counted. One could begin by looking at a series of measurements of the numbers of particular species through time. However, it would still be necessary to decide which changes in numbers through time are significant, and how to determine what causes the changes in numbers. Thus, it is more sensible to begin with models that relate changes in population numbers through time to underlying assumptions. The models will provide indications of what features of changes in numbers are important and what measurements are critical to make, and they will help determine what the cause of changes in population levels might be.

To understand the dynamics of biological populations, the study starts with the simplest possibility and determines what the dynamics of the population would be in that case. Then, deviations in observed populations from the predictions of that simplest case would provide information about the kinds of forces shaping the dynamics of populations. Therefore, in describing the dynamics in this simplest case it is essential to be explicit and clear about the assumptions made. It would not be argued that the idealized population described here would ever be found, but that focusing on the idealized population would provide insight into real populations, just as the study of Newtonian mechanics provides understanding of more realistic situations in physics.

Population migration

The vast majority of people continue to live in the countries where they were born —only one in 30 are migrants.

In most discussions on migration, the starting point is usually numbers. Understanding changes in scale, emerging trends, and shifting demographics related to global social and economic transformations, such as migration, help us make sense of the changing world we live in and plan for the future. The current global estimate is that there were around 281 million international migrants in the world in 2020, which equates to 3.6 percent of the global population.

Overall, the estimated number of international migrants has increased over the past five decades. The total estimated 281 million people living in a country other than their countries of birth in 2020 was 128 million more than in 1990 and over three times the estimated number in 1970.

There is currently a larger number of male than female international migrants worldwide and the growing gender gap has increased over the past 20 years. In 2000, the male to female split was 50.6 to 49.4 per cent (or 88 million male migrants and 86 million female migrants). In 2020 the split was 51.9 to 48.1 per cent, with 146 million male migrants and 135 million female migrants. The share of

Introduction

This report presents projections of population from 2015 to 2025 by age and sex for Illinois, Chicago and Illinois counties produced for the Certificate of Need (CON) Program. As actual future population trends are unknown, the projected numbers should not be considered a precise prediction of the future population; rather, these projections, calculated under a specific set of assumptions, indicate the levels of population that would result if our assumptions about each population component (births, deaths and net migration) hold true. The assumptions used in this report, and the details presented below, generally assume a continuation of current trends.

Methodology These projections were produced using a demographic cohort-component projection model. In this model, each component of population change – birth, death and net migration – is projected separately for each five-year birth cohort and sex. The cohort – component method employs the following basic demographic balancing equation: P1 = P0 + B – D + NM Where: P1 = Population at the end of the period; P0 = Population at the beginning of the period; B = Resident births during the period; D = Resident deaths during the period; and NM = Net migration (Inmigration – Outmigration) during the period. The model roughly works as follows: for every five-year projection period, the base population, disaggregated by five-year age groups and sex, is “survived” to the next five-year period by applying the appropriate survival rates for each age and sex group; next, net migrants by age and sex are added to the survived population. The population under 5 years of age is generated by applying age specific birth rates to the survived females in childbearing age (15 to 49 years).

Base Population These projections began with the July 1, 2010 population estimates by age and sex produced by the U.S. Census Bureau. The most recent census population of April 1, 2010 was the base for July 1, 2010 population estimates.

Special Populations In 19 counties, the college dormitory population or adult inmates in correctional facilities accounted for 5 percent or more of the total population of the county; these counties were considered as special counties. There were six college dorm counties (Champaign, Coles, DeKalb, Jackson, McDonough and McLean) and 13 correctional facilities counties (Bond, Brown, Crawford, Fayette, Fulton, Jefferson, Johnson, Lawrence, Lee, Logan, Montgomery, Perry and Randolph) that qualified as special counties. When projecting the population, these special populations were first subtracted from the base populations for each special county; then they were added back to the projected population to produce the total population projections by age and sex. The base special population by age and sex from the 2010 population census was used for this purpose with the assumption that this population will remain the same throughout each projection period.

Mortality Future deaths were projected by applying age and sex specific survival rates to each age and sex specific base population. The assumptions on survival rates were developed on the basis of trends of mortality rates in the individual life tables constructed for each level of geography for 1989-1991, 1999-2001 and 2009-2011. The application of five-year survival rates provides a projection of the number of persons from the initial population expected to be alive in five years. Resident deaths data by age and sex from 1989 to 2011 were provided by the Illinois Center for Health Statistics (ICHS), Illinois Department of Public Health.

Fertility Total fertility rates (TFRs) were first computed for each county. For most counties, the projected 2015 TFRs were computed as the average of the 2000 and 2010 TFRs. 2010 or 2015 rates were retained for 2020 projections, depending on the birth trend of each county. The age-specific birth rates (ASBR) were next computed for each county by multiplying the 2010 ASBR by each projected TFR. Total births were then projected for each county by applying age-specific birth rates to the projected female population of reproductive ages (15 to 49 years). The total births were broken down by sex, using an assumed sex-ratio at birth. These births were survived five years applying assumed survival ratios to get the projected population for the age group 0-4. For the special counties, special populations by age and sex were taken out before computing age-specific birth rates. The resident birth data used to compute age-specific birth rates for 1989-1991, 1999-2001 and 2009-2011 came from ICHS. Births to females younger than 15 years of age were added to those of the 15-19 age group and births to women older than 49 years of age were added to the 45-49 age group.

Net Migration Migration is the major component of population change in Illinois, Chicago and Illinois counties. The state is experiencing a significant loss of population through internal (domestic migration within the U.S.) net migration. Unlike data on births and deaths, migration data based on administrative records are not available on a regular basis. Most data on migration are collected through surveys or indirectly from administrative records (IRS individual tax returns). For this report, net migration trends have been reviewed using data from different sources and methods (such as residual method) from the University of Wisconsin, Madison, Illinois Department of Public Health, individual exemptions data from the Internal Revenue Service, and survey data from the U.S. Census Bureau. On the basis of knowledge gained through this review and of levels of net migration from different sources, assumptions have been made that Illinois will have annual net migrants of -40, 000, -35,000 and -30,000 during 2010-2015, 2015-2020 and 2020-2025, respectively. These figures have been distributed among the counties, using age and sex distribution of net migrants during 1995-2000. The 2000 population census was the last decennial census, which included the question “Where did you live five years ago?” The age and sex distribution of the net migrants was derived, using answers to this question. The net migration for Chicago has been derived independently, using census survival method for 1990-2000 and 2000-2010 under the assumption that the annual net migration for Chicago will be -40,000, -30,000 and -25,000 for 2010-2015, 2015-2020 and 2020-2025, respectively. The age and sex distribution from the 2000-2010 net migration was used to distribute the net migrants for the projection periods.

Conclusion These projections were prepared for use by the Certificate of Need (CON) Program; they are produced using evidence-based techniques, reasonable assumptions and the best available input data. However, as assumptions of future demographic trends may contain errors, the resulting projections are unlikely to be free of errors. In general, projections of small areas are less reliable than those for larger areas, and the farther in the future projections are made, the less reliable they may become. When possible, these projections should be regularly reviewed and updated, using more recent birth, death and migration data.

In 2024, white Americans remained the largest racial group in the United States, numbering just over 254 million. Black Americans followed at nearly 47 million, with Asians totaling around 23 million. Hispanic residents, of any race, constituted the nation’s largest ethnic minority. Despite falling fertility, the U.S. population continues to edge upward and is expected to reach 342 million in 2025. International migrations driving population growth The United States’s population growth now hinges on immigration. Fertility rates have long been in decline, falling well below the replacement rate of 2.1. On the other hand, international migration stepped in to add some 2.8 million new arrivals to the national total that year. Changing demographics and migration patterns Looking ahead, the U.S. population is projected to grow increasingly diverse. By 2060, the Hispanic population is expected to grow to 27 percent of the total population. Likewise, African Americans will remain the largest racial minority at just under 15 percent.

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15,341 DAYS (October 1st, 1979 - September 30th, 2021)

This is a dataset that describes annual statistics regarding US immigration between the 1980-2021 fiscal years.

All data are official figures from the Department of Homeland Security's government website that have been compiled and structured by myself. There are several reasons for the decision to only examine immigration data from 1980 to 2021. Since 1976, a fiscal year for the US government has always started on October 1st and ended the following year on September 30th. If the years prior to 1976 were included, the data may be incorrectly represented and cause further confusion for viewers. Additionally, the United States only tracked refugee arrivals after the Refugee Act of 1980, a statistic that is prominently featured in the dataset. As a result, the start date of 1980 was chosen instead of 1976.

Data Sources

The primary data sources used were the "Yearbook of Immigration Statistics" webpages from the Department of Homeland Security. As a whole, the website not only provided figures about US immigration that were perfect for making time series analyses, but also explored the logistics behind the annual trends found.

1. The Department of Homeland Security's 2021 Yearbook of Immigration Statistics - The Office of Immigration Statistics' 2021 Flow Reports and Population Estimates provide text, tables, and charts on lawful permanent residents, refugees and asylees, nonimmigrant admissions, naturalizations, enforcement actions, and the unauthorized population. Being the latest version released to date, the 2021 yearbook is the most comprehensive report publicly available and tends to feature data of past years for reference.
2. The Department of Homeland Security's Directory of Past Immigration Yearbooks - Past yearbooks were referenced in order to find the missing data from the fiscal years during 2000-2021. There is a single yearbook covering the fiscal years during 1996-1999, but that was the oldest publications featured in the directory.
3. The Center for Immigration Studies's File Library - In order to procure immigration data during the fiscal years of 1980-1999, I found free versions of the Immigration and Naturalization Service's paywalled yearbooks from the Center for Immigration Studies. By doing so, I was able fill in the missing values and finish the dataset.

Statistics Being Tracked

• Immigrants Obtaining Lawful Permanent Resident Status - Number of immigrants who obtained lawful permanent resident status in the United States, otherwise known as green card holders.
• Refugee Arrivals - Number of refugees who arrived in the United States. Excludes Amerasian immigrants except for the fiscal years of 1989 and 1991. Figures are based on refugee's arrival date.
• Noncitizen Apprehensions - Number of noncitizens apprehended in the United States. Data from 2020 to 2021 includes U.S. Customs and Border Protection (CBP) encounters that resulted in expulsion on public health grounds (due to the pandemic).
• Noncitizen Removals - Number of noncitizens removed from the United States. Removals are the compulsory and confirmed movement of an inadmissible or deportable noncitizen out of the United States based on an order of removal.
• Noncitizen Returns - Number of noncitizen returns from the United States. Returns are the confirmed movement of an inadmissible or deportable noncitizen out of the United States not based on an order of removal.

Dataset History

2023-01-07 - Dataset is created (465 days after the end of the 2021 fiscal year).

GitHub Repository - The same data but on GitHub.

Code Starter

Link to Notebook

About this dataset

Context

The dataset tabulates the Nottawa township population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). It lists the population in each age cohort group along with its percentage relative to the total population of Nottawa township. The dataset can be utilized to understand the population distribution across children, working population and senior population for dependency ratio, housing requirements, ageing, migration patterns etc.

Key observations

The largest age group was 18 to 64 years with a poulation of 2,020 (54.48% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2019-2023 5-Year Estimates.

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2019-2023 5-Year Estimates.

Age cohorts:

• Under 18 years
• 18 to 64 years
• 65 years and over

Variables / Data Columns

• Age Group: This column displays the age cohort for the Nottawa township population analysis. Total expected values are 3 groups ( Children, Working Population and Senior Population).
• Population: The population for the age cohort in Nottawa township is shown in the following column.
• Percent of Total Population: The population as a percent of total population of the Nottawa township is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for Nottawa township Population by Age. You can refer the same here

Data Source: CA Department of Finance, Demographic Research Unit

Report P-3: Population Projections, California, 2010-2060 (Baseline 2019 Population Projections; Vintage 2020 Release). Sacramento: California. July 2021.

This data biography shares the how, who, what, where, when, and why about this dataset. We, the epidemiology team at Napa County Health and Human Services Agency, Public Health Division, created it to help you understand where the data we analyze and share comes from. If you have any further questions, we can be reached at epidemiology@countyofnapa.org.

Data dashboard featuring this data: Napa County Demographics https://data.countyofnapa.org/stories/s/bu3n-fytj

How was the data collected? Population projections use the following demographic balancing equation: Current Population = Previous Population + (Births - Deaths) +Net Migration

Previous Population: the starting point for the population projection estimates is the 2020 US Census, informed by the Population Estimates Program data.

Births and Deaths: birth and death totals came from the California Department of Public Health, Vital Statistics Branch, which maintains birth and death records for California.

Net Migration: multiple sources of administrative records were used to estimate net migration, including driver’s license address changes, IRS tax return data, Medicare and Medi-Cal enrollment, federal immigration reports, elementary school enrollments, and group quarters population.

Who was included and excluded from the data? Previous Population: The goal of the US Census is to reflect all populations residing in a given geographic area. Results of two analyses done by the US Census Bureau showed that the 2020 Census total population counts were consistent with recent counts despite the challenges added by the pandemic. However, some populations were undercounted (the Black or African American population, the American Indian or Alaska Native population living on a reservation, the Hispanic or Latino population, and people who reported being of Some Other Race), and some were overcounted (the Non-Hispanic White population and the Asian population). Children, especially children younger than 4, were also undercounted.

Births and Deaths: Birth records include all people who are born in California as well as births to California residents that happened out of state. Death records include people who died while in California, as well as deaths of California residents that occurred out of state. Because birth and death record data comes from a registration process, the demographic information provided may not be accurate or complete.

Net Migration: each of the multiple sources of administrative records that were used to estimate net migration include and exclude different groups. For details about methodology, see https://dof.ca.gov/wp-content/uploads/sites/352/2023/07/Projections_Methodology.pdf.

Where was the data collected?  Data is collected throughout California. This subset of data includes Napa County.

When was the data collected? This subset of Napa County data is from Report P-3: Population Projections, California, 2010-2060 (Baseline 2019 Population Projections; Vintage 2020 Release). Sacramento: California. July 2021.

These 2019 baseline projections incorporate the latest historical population, birth, death, and migration data available as of July 1, 2020. Historical trends from 1990 through 2020 for births, deaths, and migration are examined. County populations by age, sex, and race/ethnicity are projected to 2060.

Why was the data collected?  The population projections were prepared under the mandate of the California Government Code (Cal. Gov't Code § 13073, 13073.5).

Where can I learn more about this data? https://dof.ca.gov/Forecasting/Demographics/Projections/ https://dof.ca.gov/wp-content/uploads/sites/352/Forecasting/Demographics/Documents/P3_Dictionary.txt https://dof.ca.gov/wp-content/uploads/sites/352/2023/07/Projections_Methodology.pdf

The Clear Lake herd contains migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Instead, much of the herd displays a nomadic tendency, slowly migrating north, east, or south for the summer using various high use areas as they move. Therefore, annual ranges were modeled using year-round data to demarcate high use areas in lieu of modeling specific winter ranges. The areas adjacent to Clear Lake Reservoir were heavily used during winter by many of the collared animals. A few collared individuals persisted west of State Route 139 year-round, seemingly separated from the rest of the herd due to this highway barrier. However, some pronghorn cross this road near Cornell and join this subgroup. Summer ranges are spread out, with many individuals moving southeast through protected forests or over the state border into Oregon. A few outliers in the herd moved long distances south, crossing State Route 139 to Oak Ridge, or east into Likely Tables pronghorn herd areas. Drought, increasing fire frequency, invasive annual grasses, and juniper encroachment negatively affect pronghorn habitat. Recent population surveys indicate a declining population (Trausch and others, 2020). Juniper removal on public and private lands has potential to improve habitat quality and potentially reduce predation (Ewanyk, 2020). These mapping layers show the _location of the migration routes for pronghorn (Antilocapra americana) in the Clear Lake population in California. They were developed from 72 migration sequences collected from a sample size of 23 animals comprising GPS locations collected every 1-6 hours.