I volunteer two Sundays a month to care for the raptors at Richardson Nature Center.
Getting ready to weigh the kestrel. I think his weight was 103g (3.6 oz or about 1/4 lb). In the summer we bring the weights down some, and in the winter feed them more so they'll have a little more insulation to work with. Some kestrels stick around for the winter, but not usually this far north. I saw some on a Christmas Bird Count further south in Northfield a couple of seasons ago. Because of the cold, this kestrel has a heater in his mew that we use during the winter, and the temperature is monitored every day.