Update for Campus Bird Watchers, Enthusiasts|
No one keeps a more watchful eye on campus flora and fauna than Lynn Mueller, landscape architect with the Office of Research Facilities. Here is his latest report from the field:
Unfortunately, 2015 was another disappointment in attracting bluebirds to nest on the campus. Just about every trail had some early spring nesting activity, but the birds, for whatever reason, were unable to follow through and successfully lay eggs. We had about a dozen bluebird nest starts. Moving many of the boxes late last spring did lower the number of invasive sparrows but did not entirely keep them away.
Once again we had a high number of house wrens—an estimated 99 fledglings. Chickadee numbers were down slightly to 18 fledged. Our greatest success was with tree swallows, who have been replacing bluebirds. We had a good estimate of 58 young tree swallows that flew away. Our highest density of tree swallows was around the stormwater pond behind the National Library of Medicine. Every house was occupied with swallows or chickadees. The plastic purple martin house was replaced with a standard aluminum house and another colony of martins moved in during the first week of April. The first house was re-occupied with 8 of the 12 apartments used. An unknown number of young from both houses left for Central America in late July.
We had one mysterious incident in June when the house along the bike path had a railing bent and a young bird killed. We had to lower the house and remove the dead bird. All others seemed to be okay. Maybe a hawk did it?
As NIH’ers know, the purpose of the 106 bluebird houses is to attract insect-eating songbirds to help control campus insect pests. Since we started the trails in 2001, we have nearly eliminated all insecticide spraying. We only sprayed some holly inside the Clinical Research Center courtyards with horticultural oil for spider mites back in July. We had another year of not having to spray any insecticides other than those few holly.
The purple martins and tree swallows cleaned up the mosquitoes at the pond. Our campus has become well-balanced with birds and beneficial insects taking out the “bad” bugs.
Last fall, we spread thousands of milkweed seeds over many of our open no-mow meadows. Some germinated this spring; maybe next year we’ll have some nice, mature patches to attract Monarch and other butterflies. You may have seen some of the signs ORF put up—“Monarch Butterfly Sanctuary” and “Pollinator Meadow.” Only a few Monarchs were seen on campus this summer, so that number can certainly improve.