April 5

     We are now entering the part of the kestrel season which I find to be the most confusing and stressful. It is always very exciting to see the first kestrels of the season beginning in mid- March.  The expectation is that as the weather warms up one would see a steadily increasing number of kestrels showing up at various boxes, but that doesn't appear to be the way it works. As the weather warms, there are times when the boxes that had kestrels very early on appear to have been completely abandoned. We are now in the period where the boxes that have been successful for the last five years appear to have absolutely no kestrel activity whatsoever. In the past this has gone on for a week or two and then suddenly, within the course of 2-3 days, there are kestrels everywhere. It is the waiting right now that is so difficult. Could this be the year when it all suddenly falls apart? Maybe. We'll have the answer to that in a couple of weeks. Right now my number one job is to keep the boxes starling free so when the kestrels do show up there will be no starlings using the boxes. By this time last year I had removed almost 30 starlings. This year so far I have removed only 5. There are any number of possible reasons for this, the most obvious being that the cold spring has pushed everything back-including the arrival of kestrels. We'll see.

     I did have one adult female capture yesterday. She was unbanded. Her weight was 133 grams which is pretty robust for this time of the year. Birds banded at this time of the year that are on the heavy side could possibly be migrants just passing through on their way to breeding farther north. There is a principle called Bergmann's rule  which postulates that species that spend most of their time in colder climates to the north tend to be heavier.  This added mass is thought to help them conserve body heat more efficiently. So far this season, the trapped birds that have been wearing bands indicating they were banded within my study area have been averaging 10-20 grams lighter than the unbanded female that was banded yesterday. It will be interesting to see if the heavier bird banded yesterday does, in fact, remain in this area to breed.