[wisb] Re: robin mortality
- From: "Mike McDowell" <mike@xxxxxxxxxxxxxxxxxx>
- To: <wisbirdn@xxxxxxxxxxxxx>
- Date: Tue, 9 Jun 2009 09:05:59 -0500
>From Birds of North America Online:
"Using field data to model a hypothetical robin population, Young (1955)
estimated the rate of survival of young from fledging to 1 Nov to be only
25%. Even so, there were estimated to be fewer adults in the population than
immatures by 1 Nov; ratio of adults to immatures estimated to be 93:100 by
Young (1955), 88:100 by Farner (1945). On the basis of 855 records of
banding returns and assuming that population was stable, Farner (1945, 1949)
estimated that the average young T. m. migratorius surviving until 1 Nov or
1 Jan will live another 1.7 yr and that there is 52%/yr (6%/mo) mortality in
all age cohorts after age of 6 mo. Thus, within 6 yr there is a nearly
complete turnover in population. Survival estimates for areas west of
Michigan were somewhat lower."
Mike McDowell
Madison - Dane County
www.birddigiscoper.com
-----Original Message-----
From: wisbirdn-bounce@xxxxxxxxxxxxx [mailto:wisbirdn-bounce@xxxxxxxxxxxxx]
On Behalf Of Cheryl Todea
Sent: Tuesday, June 09, 2009 8:00 AM
To: wisbirdn@xxxxxxxxxxxxx
Subject: [wisb] robin mortality
Does anyone know what the average mortality rate is for robin chicks?
Cheryl Todea
Trees For Tomorrow
P.O. Box 609
Eagle River, WI 54521
715-479-6456 X235
cheryl@xxxxxxxxxxxxxxxxxxxx
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