Friday, June 1, 2018

Unique Nest Box Discovery

Written by Judy Schwarzmeier

Members of the Beaver Creek Reserve banding crew have been out checking American Kestrel Nestboxes and had a unique discovery recently.  

American Kestrel 1783-89541 was banded on July 5, 2016 when it was still a baby in the nest.  (The 'nest' is in a box made for birds of this size, filled with wood shavings, and placed on a tall pole.)  Judy Schwarzmeier, one of Beaver Creek Reserve's volunteer bird banders, put the band on the young bird's leg that day.  At the time we could not tell whether 1783-89541 was a boy or a girl because it just had the downy white pin feathers of a baby, with no distinguishing adult feathers.  It couldn't fly and needed both its mom and dad to bring food to it and its four siblings.  

It grew up in one of several nest boxes along County Hwy D in eastern Eau Claire County that the BCR banders have been monitoring.  Once 1783-89541 was able to fly and hunt for food on her own, she probably left our area and went south for the winter, perhaps to central or southern areas of the U.S.  

Then two years later on May 21, 2018, when the kestrel banding crew was out doing theirregular nest box check, one box had an adult female sitting on five eggs.  She had a band on her leg, which turned out to be 1783-89541!  She was not in the same box where she grew up, but in a different one just a few miles down the road on County Hwy D from the one where she had hatched and fledged.  

The kestrel crew was very excited when they looked back in the old banding records to see when and where the band with the number 1783-89541 had been used.  It might not seem like a big deal, but this is the first time in all our years of monitoring kestrel nest boxes (about 12 years or more, during which we've banded hundreds of young kestrels), that one of our banded babies has returned as an adult in a subsequent year to make a home in one of our nest boxes and raise her own family.

Part of the reason for the rarity of such an event is that wild animals, in general, have a very high mortality rate in their first year of life.  It's a tough world out there, and very few survive.  And the American Kestrel as a species is in a general decline in the U.S.  One reason might be that these days it is harder to find suitable tree cavities in which to make their nests.  Most trees with large holes get cut down.  We hope that providing nest boxes may help to boost the survival of this species..  
  
We will keep watching 1783-89541 for the rest of the 2018 nesting season to see if her five eggs hatch and perhaps we'll even band her babies before they fledge.  We feel a bit like proud parents!  As well, we have a sense of satisfaction that our efforts to learn about a small part of the natural world will contribute to its survival.