Subject: [Tweeters] Eurasian Collared-Dove spread!
Date: Nov 29 22:02:22 2010
From: Eugene and Nancy Hunn - enhunn323 at comcast.net


Evan, tweets,



I believe it is also the case the Eurasian Collared-Dove greatly expanded
its European range in the past few decades from the eastern Mediterranean
now all the way to Scotland and perhaps beyond. I like to entertain the
possibility that this explosive expansion of range could well have brought
collared-doves across the Atlantic on their own, as apparently was the case
with the Cattle Egret. In that case they would not be an "introduced"
species.



Gene Hunn

Sonoma, CA

enhunn323 at comcast.net



From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Evan
Houston
Sent: Monday, November 29, 2010 1:26 PM
To: Tweeters
Subject: [Tweeters] Eurasian Collared-Dove spread!



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.htm
l



>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