Just a note to mention that I have had birds returning as early as late
March since the mid-1970s when we begin some work on Purple Martins in PG
and Montgomery counties. There may be a connection to older birds
returning earlier than younger ones and to the same colonies. We found
that many of the adults banded returned to the same colonies year after
year. We even had a mated pair that returned to the same house and
compartment in a subsequent year. The older males return first (full male
plumage) followed closely by the older females (usually darker underneath
than first year breeding females), then followed by subadult males and
females. We have had broods old enough to band in late May and other nests
that still have building going on and eggs not yet laid at the same time.
This timing does seem to be influenced by the weather during spring.
Cheers,
Kathy
M. Kathleen Klimkiewicz, Biologist
USGS Patuxent WRC BBL
12100 Beech Forest RD STE 4037
Laurel MD 20708-4037
301-497-5795 work
Fax 301-497-5717
Report bands: reportband.gov and get instant feedback!
http://www.pwrc.usgs.gov/bbl
James Tyler Bell <>
Sent by: Maryland Birds & Birding <>
03/20/2008 08:59 AM
Please respond to
James Tyler Bell <>
To
cc
Subject
Re: [MDOSPREY] Purple Martins are back
Out of curiosity, I plotted Stephen's PUMA arrival dates into Excel and
ran a regression. The data is surprisingly tight with an R-squared of
0.824 (1.000 is a perfect correlation). Then I ran the data out a few more
years assuming a continuing trend and I got the data below. Of course,
it's not likely that if you continue the line through 2044 that they'll
basically be arriving on Christmas Day but still, it's got to show
something about warming that they've basically returned an entire month
early since he began his observations!
Real arrival Regression line
(predicted arrival)
4/16/1999 4/11/1999
4/8/2000 4/7/2000
4/3/2001 4/6/2001
3/30/2002 4/4/2002
4/4/2003 4/1/2003
3/26/2004 3/29/2004
3/28/2005 3/27/2005
3/30/2006 3/25/2006
3/24/2007 3/23/2007
3/19/2008 3/19/2008
3/18/2009
3/16/2010
3/13/2011
3/10/2012
3/9/2013
3/6/2014
3/4/2015
3/1/2016
12/26/2043
12/23/2044
Tyler Bell
California, Maryland
----- Original Message ----
From: Stephen Hult <>
To:
Sent: Wednesday, March 19, 2008 5:58:13 PM
Subject: [MDOSPREY] Purple Martins are back
Five adult male Purple Martins just returned to my colony in Edgewater MD.
This is by far to earliest they have ever returned. In past years they
have
returned on the following dates:
1999 April 16
2000 April 8
2001 April 3
2002 March 30
2003 April 4
2004 March 26
2005 March 28
2006 March 30
2007 March 24
2008 MARCH 19
Stephen Hult
Edgewater Maryland
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