First Kestrel Eggs for 2018

A break in the wet spring weather gave me the chance to peek into one of my kestrel boxes this morning. I'm happy to say that the female is in the process of laying her clutch. Three eggs are visible in the video clip. That puts the first egg date at 21-22 April and clutch completion 28-30 April, depending on the final egg count. I was glad to see this pair establish their territory early, which gave them a leg up on any starlings that had ideas about using this box. Additionally, this female is new at this box, as last year's bird was/is banded. 

More occupied boxes to check this week, weather permitting. I wanted to give the birds a little space this year during pre-laying and laying, so I suspect one or two other pairs are at a similar stage in the laying process. Maybe even a bit further on. More video clips to come.

Eggs Coming and New Box Occupants

It's the 3rd week in April and the forecast tonight calls for snow. Come on! While winter is officially over, it is not going out without a fight. I, for one, am done with it. On a positive note, kestrels are occupying several nest boxes in Ulster County. In 2017, the first kestrel eggs were laid on April 24th. I hope to have a look inside occupied boxes in a few days to see if egg-laying has begun. The birds seem to be on a similar schedule to last year, even though this April has been a lot cooler with more precipitation. Stay tuned...I will post some video clips or photos of the upcoming camera checks.

As birds set up breeding territories and occupy nest boxes, I've been looking for banded birds from last year. The male in the above photo nested last year at one of the Shawangunk Grasslands NWR boxes and has been on his nesting territory since at least January. He may have wintered in the area. Anyway, his apparent mate for this year is completely unbanded. I banded the br…

Summing Up 2017, Winter Notes and Spring 2018 Just Around the Corner

This summary is way overdue. Better late than never.

The kestrels here in Ulster County had a seemingly rough time of it in 2017. Lots of starlings in this area create stiff competition for nest boxes, which are premium nesting sites for cavity-nesting birds. The rich habitat and abundant nest sites (boxes) at Shawangunk Grasslands NWR create an ideal situation for breeding kestrels. As in 2016, all 6 boxes at the refuge were occupied in 2017. While last year saw all 6 pairs raise successful broods, only three pairs were successful this year. Birds fared even worse at other monitored boxes in the county, with only 3 pairs pulling off young out of 18 boxes. Anyway, here are some statistics from the 2017 Breeding Season.

2017 Productivity

- Kestrels occupied 17 boxes out of 24 total -  71% Occupancy, which is pretty good.
- Only 6 boxes were successful (3 at Shawangunk Grasslands, 3 elsewhere in the county).*
- A total of 61 eggs were laid spread over 13 of the occupied boxes. Average c…

Spring Weather, Chick Banding and some Fledglings

A lot has been happening since my last post. Some good, some not so good. We've had a cool, wet spring here in the mid-Hudson Valley which can be the kiss of death for bird nesting. A few of our kestrel pairs have failed, either at the egg or nestling stage and I suspect this weather is at least partly to blame. By early June, we had 18 of 25 boxes where kestrel pairs were at least observed to have started a breeding attempt, but now the number of active pairs is down to 7. In addition to the less-than-ideal weather, starlings were a major cause of low kestrel occupancy. I will be thinking about re-siting some boxes next year to make them more appealing to kestrels.

One box had an interesting and dark story. The female laid 5 eggs and I did a hatching check and found three, 4-5 day old chicks and two eggs. Unhatched eggs...that happens. But when I returned a week later to get a better idea of chick age, the box was totally empty. Something had grabbed those chicks out of the 3-inc…


Kestrel eggs are hatching here in Ulster County. I inspected two boxes yesterday at the Shawangunk Grasslands and they had chicks between 4-8 days old. In the first one, all 5 eggs hatched, but there were still two eggs left in the second one along with 3 nestlings. It is likely those remaining 2 eggs will not hatch. Aging chicks between 4-9 days old is challenging because none of their flight or body feathers have emerged...they are all white fluff. How alert and mobile they are helps narrow the estimate to either end of that window. 
The following two videos are nest checks from yesterday. Excuse the poor video quality...this is a low-budget project. Looking forward to banding nestlings in a couple weeks and getting important feather samples for the American Kestrel Genoscape Project ( These folks just got big chunk of $$ to study birds and climate change. Important work. 

I had a mild surprise today during a box check. Surpr…

Foreign Recovery, Clutch Sizes and Hatching Imminent

Since my last post, the kestrels have been diligently incubating eggs, fighting off unruly starlings and tolerating my occasional intrusions into their homes. It must be disconcerting when a large, foreign object (usually a coconut water can on a pole) blocks your front doorway. But they continue tending their clutches with biological determination. Unfortunately, a couple of pairs have abandoned boxes due to the intense competition with starlings in this area. I will probably move a couple of the boxes next year to areas where these pesky, non-native birds are less abundant. 
I finalized my inventory of all the occupied boxes for complete clutches (total eggs laid). From 11 occupied boxes, a total of 54 eggs have been laid. This comes to 4.91 eggs/occupied box. I suspect a small number eggs won't hatch, so I'll maybe have 50 nestlings to band. Should be fun. 
I've also banded a few more adults, which can be seen in the following photos. I trapped the first male near his …

Kestrel Eggs Appearing in Ulster County

Yesterday was my day to make the rounds of the nest boxes and check for eggs. Since rain was forecasted for today (correctly) and I hadn't checked most boxes for about 10 days, I needed to see nest contents before clutches were complete, which typically takes 9 days. I was really hoping for eggs and was not disappointed. Five of the boxes had either one or two eggs. Here's what the inside of three boxes looked like yesterday: 

The female from the box with two eggs likely began laying, at the earliest, on 20 April. An average clutch is 5 eggs, so if she lays one egg every other day, her clutch should be complete around 29 April and her eggs should hatch sometime around 1 June (incubation takes about a month). Box checks with incomplete clutches are ideal, because now I know roughly when incubation will start and the eggs will hatch. If my first look at eggs was of a complete clutch, the female could have completed yesterday or a week ago...not ideal. I will estimate clutch com…