Introduction History
European starlings were introduced to North America in 1890 as part of an American Acclimatization Society initiative to populate Central Park with the birds from Shakespeare’s plays (Cabe, 1993). There were many species of birds mentioned in Shakespeare, but not all were able to survive and thrive in the new North American climate. The initial introduction consisted of approximately 60 individuals released in 1890 and 40 more in 1891, leading to a total of ~100 individuals released into Central Park in New York City (Cabe, 1993). From this founding population, starlings have expanded their range across all of North America where their current population exceeds 200 million individuals, over one-third of the global population of this species (Feare, 1984). This range expansion that has taken place in the last 128 years, demonstrating that they are able to rapidly adapt to new surroundings and are incredibly versatile.
Other starling introductions from the 19th century have been previously studied using genetics, including the mid-19th century Australian introduction (Rollins et al, 2009; Rollins et al, 2011; Rollins et al, 2016) and the late 19th century South African introduction (Berthouly-Salazar et al, 2013). During introductions, the often small number of founding individuals may result in a genetic bottleneck and, therefore, these populations are likely to have lower genetic diversity than those in the native range. This was demonstrated using data from the UK and Australia (Rollins et al, 2011). However, because multiple introductions were made to Australia (Jenkins 1959), and these occurred prior to and had a greater number of propagules than the New York introduction, we predict that the genetic diversity of the North American population will be lower than that of Australia. It is also of note that populations of North American and Australian birds increased exponentially following introduction (Bitton and Graham, 2014; Long, 1981), which may mitigate loss of genetic diversity from the founder population. In Australia, population expansion has been limited by large expanses of arid environment, which may have affected population growth and expansion on this continent.