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…

Shawanagunk Grasslands Kestrel Density

The Shawangunk Grasslands NWR (SGNWR) outside of Shawangunk, NY. is a gem of open country habitat that is locally and regionally important for many bird species. Most of its 597 acres (~240 hectares for the metric savvy) are grasslands, which is in short supply in the northeastern US. Bobolinks, Grasshopper and Vesper Sparrows are threatened nesters. Upland Sandpipers stop here annually during spring migration. Short-eared Owls and Northern Harriers form impressive winter concentrations. It is simply THE place to go in the immediate area to see Short-eared Owls. The refuge was established in 1999 after conversion from a military airfield and is designated an Important Bird Area by Audubon NY. It is definitely worth a visit. For more information, see
This vital patch of habitat was the foundation for the kestrel nest box project. I noticed the boxes on my first visit in November 2015 and learned that the boxes were occupied e…

Box Occupancy Update, Landowners and first Male capture

It's still early days, but the nest boxes are filling up fast. Kestrels are on the move throughout the eastern US and I'm finding birds all over Ulster County. Of the 25 boxes being monitored for this project, fourteen are currently occupied by at least one kestrel. I'm sure some of the birds I'm seeing are migrants simply popping up in open habitat...a nice confirmation that I'm putting boxes in suitable areas. Once the migrants move out the picture will be clearer.

One of the joys of this project has been meeting several local landowners. Ulster County is largely rural with many farms, ranches, vineyards and orchards. Many of the folks hosting kestrel boxes are genuinely interested in coexisting with wildlife on their lands. One of my major goals with monitoring kestrels at nest boxes is building this network and platform for local wildlife conservation, appreciation and advocacy.

I've received a few comments from landowners and interested folks about box pl…