Lee's questions make me wonder if perhaps others have missed the wealth of
information available from the recently completed second Breeding Bird
Atlas.  The committee is now synthesizing all this information, combined
with data from the long running Breeding Bird Surveys, for publication later
this year.  In the meantime everyone can learn a lot from looking at some of
the data presented at http://bba.iowabirds.org/.  I just looked at the
species account for Northern Mockingbird and was a bit surprised comparing
the results from 20 years ago to now.  Less scientific but also interesting
is the mapping of reports to our seasonal field reports -
http://iowabirds.org/Birds/SpeciesMapping.aspx. 

I am also interested in the increase in reports of both southern and western
birds.  Neotropic Cormorant has gone from a first state record not so long
ago to now breeding in the state.  Reports of Lazuli and Painted Buntings
have increased in recent years.  My gut feeling is that after the big influx
of Great-tailed Grackles they are now harder to find, at least here in south
central Iowa.  We are doing some mapping of vagrant birds so this is a good
time to remind folks that the end of the spring season is rapidly
approaching and we can only analyze what you report through seasonal field
reports and the records committee documentation form for casual and
accidental species.

Ann Johnson
Norwalk, IA



-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Leland
Searles
Sent: Friday, May 17, 2013 10:41 PM
To: IA-BIRD
Subject: [ia-bird] Mockingbird, Des Moines

A Northern Mockingbird came to the oriole feeder this morning. It fed on
grape jelly briefly, then stayed around as Baltimores came by. Finally,
after quite a few photos, it flew into the yard.

I've been curious to know if there are any studies that show changes in the
population centers of our breeding birds. These would parallel the analyses
by National Audubon, using 40 or so years of winter bird count data. The
winter data show sometimes marked shifts in winter populations, often to the
north (about two thirds of the 300 plus species) or in other directions
(about one third). The movements generally conform to what one would expect
from climate change.

The presence of the mockingbird has me wondering about this species,
"specifically." As a youth, I knew it to expand its range a little north
during winter, into southern Iowa. Occasional mockers would show up on
winter counts, often near large red cedars with a good berry crop. Those
birds returned to Missouri in the summer.

Other birds with known northward expansion include Great-Tailed Grackles,
and it's my impression each spring that a wider array of southern and
western species get blown off course into Iowa, on the way elsewhere.
Recall that a Mountain Bluebird, a Lazuli Bunting, Bewick's Wrens, and
several others have been seen just this year and reported here.

Anyhow, if there are studies on breeding bird populations, or if any BBS
participants have stories or conclusions to share, I'm curious.

Thanks,

Lee Searles
Des Moines



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