Survey of Artificial Nest Boxes and Tree Cavities for Secondary Cavity Nesting Avifauna in Northern New York
Cavity nesting species use tree holes which result from either prior excavation activity or decay due to branch damage or disease. These tree cavities serve as an important refuge for safety, shelter, and nesting sites. Avian cavity nesters are classified as primary (i.e., excavate their own cavities) or secondary (i.e., occupy naturally occurring cavities or existing cavities created by primary excavators). During May-September 2016, cavity nesting of secondary cavity nesters Falco sparverius (American Kestrel) and three species of waterfowl, specifically Aix sponsa (Wood Duck), Lophodytes cucullatus (Hooded Merganser), and Bucephala clangula (Common Goldeneye) was monitored at Lake Alice Wildlife Management Area (LAWMA), Clinton County, NY. Goals of the monitoring were threefold, 1) monitor the 17 artificial waterfowl nest boxes and 3 American Kestrel boxes; 2) survey natural tree cavities in adjacent forest to gain baseline occupancy information; 3) compare results of artificial waterfowl nest box occupancy to those of prior years under monitoring by the NYS Department of Environmental Conservation. Of the 17 waterfowl nest boxes, only 29% (n = 5) contained Wood Duck nests, of which two were unsuccessful. Of the 46 total eggs, 50% (n = 23) hatched successfully. The three American Kestrel boxes failed to attract the target species, but were occupied by Tachycineta bicolor (Tree Swallow). Tree cavities were surveyed using line transect sampling and occupants were observed using an extension pole and GoPro camera accessed using a smartphone mobile app. Twenty-nine natural tree cavities and 2 abandoned passerine nests (south-facing) were noted in 19 trees ranging in diameter at breast height from 22-79 cm and comprised of 42% (n = 8) Acer rubrum (Red Maple), 11% (n = 2) Acer saccharum (Sugar Maple), 5% (n = 1) Fraxinus americana (White Ash), and 42% (n = 8) snags. Woodpeckers excavated 62% (n = 18) and 38% (n = 11) were natural limb and canopy damage. With 29% occupancy rates and 50% unhatched eggs observed at LAWMA, we recommend relocating underused or ineffectively placed nest boxes, especially those adjacent pools which have since dried.