NestWatch 2017: Summer Update

NestWatch training at VINS (Nathan Thoele)

A young visitor noticed me sticking a long, bent pole up into the rafters of the Nature Nook last month. “What are you doing? What’s up there?”

“I don’t know yet—do you want to help me find out?” I asked.

Pointing her towards the mirror that was duct-taped to the bent part of the pole, we peered up together, where the mirror extended over the top of the rafter and quickly revealed a hidden treat—a nest!

This one belonged to an Eastern Phoebe, and I’d seen the adult several times returning to this spot with tiny caterpillars in its beak, which must have been breakfast for the growing young. The eggs had already hatched, and the fuzzy gray nestlings contained inside were packed closely together in a heap, and difficult to distinguish from one another.

After a few seconds, moving the mirror for a better angle, we decided there were three phoebe nestlings. I pulled the mirror down and helped our visitors record this observation—3 partly feathered young, no eggs, no adult nearby—on a clipboard. “Now you’re a citizen scientist!”

Western Screech Owl nestlings (Lee-Hong Chang)

Through the citizen science project NestWatch, run by the Cornell Lab of Ornithology, VINS has been monitoring its local nesting birds since 2013, in order to help scientists better understand breeding biology. Our staff and lucky visitors gather valuable data on the timing of laying and hatching, the number of eggs laid, and the behavior of the adult birds, among other things. The information is uploaded online, and though it is completely free for the scientists and participants, NestWatch has generated mountains of data and aided the publication of dozens of scientific papers. There is also a photo contest for participants every year, and who can resist browsing through photos of cute baby birds?

That phoebe nest was one of 2 at VINS this summer. In fact, 2017 was quite busy, the campus hosted 2 House Wren nests, 1 Red-eyed Vireo nest, 1 Black-capped Chickadee nest, 11 American Robin nests, and 5 Tree Swallow nests. Here is a bit of our data:

	American Robin	House Wren	Eastern Phoebe	Tree Swallow	Black-capped Chickadee	Red-eyed Vireo
Nests Monitored	11	2	2	5	1	1
1st Egg Date	27 April	20 May	< 28 May	28 May	30 May	27 June
Total Eggs	31	13	> 3	21	10	3
Live Young/Nest	2	6	3	2.6	7	0
Nest Success**	70%	76%	50%	53%	70%	0%

Tree Swallow adult (Bren Lundborg)

Two of our American Robin pairs double-clutched, or raised two complete sets of young sequentially in the same nest. If food is available early enough in the spring, and consistently available through the summer, many birds try to squeeze in an extra breeding attempt. We even had one robin triple-clutch, but for a different reason than abundant food. This bird decided one of the lights by the Administration building would be a great place to nest, and as visitors moved past every day, just inches away, the robin kept abandoning her nest, and knocked her first two eggs onto the ground. This was followed by a second and third attempt before she decided to find a more suitable location.