02 October 2011

The starlings are back, it must be autumn

As a transplant to the tropics, I can't always tell when the seasons change. However, this sight always lets me know its autumn.

Those birds on that wire are Common European Starlings (Sturnus vulgaris) and they're an invasive species introduced to North America in 1890 and 1891 when between 60 and one hundred birds were released in Central Park in New York. A society led by a man named Eugene Schieffelin wanted to introduce to North America all of the birds mentioned by Shakespeare. It's from those 60 to 100 birds that all 200,000,000 starlings that call North America home are descended.

Even though their a non-native species, they've figured out how to migrate to warmer climates in the winter. That amazes me to no end. In addition to their ability to figure out migration patterns, starlings are pretty amazing creatures despite the fact that they're an invasive species.

  • Both males and females can mimic human speech. (Some people keep starlings as pets). Some starlings also imitate the song of many other birds like the Eastern Wood-Pewee, Meadowlark, Northern Bobwhite and House Sparrow, along with Blue Jays, Red-Tailed Hawks and Cedar Waxwings. Vocalizations inside the nestbox during nest building can be lengthy and quite varied.
  • An estimated 1/3 to 1/2 of returning females nest in the same box or area in consecutive years. That is why it's even more important not to let them nest in the first place.
  • A starling couple can build a nest in 1-3 days. Both sexes incubate.
  • A migrating flock can number 100,000 birds. They roost communally in flocks that may contain as many as a million birds. Watch this amazing video of a swarming flock of starlings that appear to be feeding.
  • Each year, starlings cause an estimated $800 million in damages to agricultural crops (Pimental et al, 2000)
  • About 15-33% of first broods are parasitized (via egg dumping) by other starlings.
  • Starlings have an unusual bill that springs open to grip prey or pry plants apart.
  • Starlings only molt once a year (after breeding) but the spots that show up in the winter wear off by the spring, making them look glossy black.
  • In Starlings, the length of the intestinal tract actually varies depending on the season. It is shorter in the summertime (when birds are mainly eating protein-rich) insect foods and larger in wintertime when they are mainly eating seeds, which are rich in carboyhydrates. (Source: Analysis of Vetebrate Structure, Hildebrand and Goslow)

I grew up learning to hate them as a scavenger and a pest but if I step away from that, they're a beautiful bird and any invasive that can figure out a migration pattern and alter the length of its alimentary canal can't be all bad. Right?

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