Hi Tweeters,

Today I came across a very interesting post by a bird blogger that illustrates
the rather amazing spread of Eurasian Collared-Doves across North America during
the past couple of decades. This blogger has used data from the bird sightings
database eBird.org to create a year-by-year animation that illustrates the rapid
westward and northward spread of this species. The animation shows an amazing
spread of green (the blog explains that green indicates presence of the species
being depicted) through the 2000s.

link (click on animated gif within this link to see the animation):
http://bbill.blogspot.com/2010/11/ebird-visualizations-eurasian-collared.html

>From the book "Birds of Washington" by Wahl, Tweit, and Mlodinow, collared-doves
apparently became established first in the Bahamas during the early 1970s due to
escapes and releases, and have been spreading across North America ever since,
with the first record for WA being in 2000.

One thing to keep in mind is that the number of users of eBird is also
increasing over time, so with fewer total sightings entered the longer you go
back, absence of a species from a given area will not be as reliable. This
increase in users over time might tend to make the spread look a bit faster than
it really was, but nevertheless the trend of spreading rapidly to the west and
north spread is undeniable.

The final point of this post is that using eBird to submit your sightings can
really contribute to very interesting research on bird distribution!

Good birding,
Evan Houston
Seattle, WA