Species with cryptic origins (i.e. those that cannot be reliably classed as native or non-native) present a particular challenge to our understanding of the generation and maintenance of biodiversity. Such species may be especially common on islands given that some islands have had a relatively recent history of human settlement. It is likely that select island species considered native might have achieved their current distributions via direct or indirect human actions. As an example, we explore the origins of eastern bluebirds (Sialia sialis bermudensis) on the island of Bermuda. Considered native to the island and a distinct subspecies, this population has diverged in morphology relative to mainland North America. Using microsatellite markers and simulation of island colonization, we show that the Bermuda population of bluebirds is the likely result of a single colonization event that occurred during the 1600s, making this a cryptic invader. To our knowledge, this is one of the young...

Marshall Islands's Number of international migrants (% of population) is 6.2% which is the 95th highest in the world ranking. Transition graphs on Number of international migrants (% of population) in Marshall Islands and comparison bar charts (USA vs. China vs. Japan vs. Marshall Islands), (Bermuda vs. Northern Mariana Islands vs. Marshall Islands) are used for easy understanding. Various data can be downloaded and output in csv format for use in EXCEL free of charge.