Seasonal diets of insectivorous birds using canopy gaps in a bottomland forest.

Journal Article · Sun Jul 01 04:00:00 EDT 2007 · Journal of Field Ornithology

DOI:https://doi.org/10.1111/j.1557-9263.2006.00081.x· OSTI ID:917770

Sorenson, Clyde E; Hanula, James L; Horn, Scott; Ulyshen, Mike D

ABSTRACT. Little is known about how insectivorous bird diets are influenced by arthropod availability and about how these relationships vary seasonally. We captured birds in forest-canopy gaps and adjacent mature forest during 2001 and 2002 at the Savannah River Site in Barnwell County, South Carolina, and flushed their crops to gather information about arthropods eaten during four periods: spring migration, breeding, postbreeding, and fall migration. Arthropod availability for foliage- and ground-gleaning birds was examined by leaf clipping and pitfall trapping. Coleopterans and Hemipterans were used by foliage- and ground-gleaners more than expected during all periods, whereas arthropods in the orders Araneae and Hymenoptera were used as, or less than, expected based on availability during all periods. Ground-gleaning birds used Homopterans and Lepidopterans in proportions higher than availability during all periods. Arthropod use by birds was consistent from spring through all migration, with no apparent seasonal shift in diet. Based on concurrent studies, heavily used orders of arthropods were equally abundant or slightly less abundant in canopy gaps than in the surrounding mature forest, but bird species were most frequently detected in gaps. Such results suggest that preferential feeding on arthropods by foliage-gleaning birds in p p habitats reduced arthropod densities or, alternatively, that bird use of gap and forest habitat was not determined y food resources. The abundance of arthropods across the stand may have allowed birds to remain in the densely vegetated gaps where thick cover provides protection from predators.

• Research Organization: USDA Forest Service, Savannah River, New Ellenton, SC
• Sponsoring Organization: USDOE - Office of Environmental Management (EM)
• DOE Contract Number: AI09-00SR22188
• OSTI ID: 917770
• Report Number(s): na; 07-05-P
• Journal Information: Journal of Field Ornithology, Journal Name: Journal of Field Ornithology Journal Issue: 1 Vol. 78; ISSN 0273-8570; ISSN JFORDM
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ABUNDANCE
ARTHROPODS
AVAILABILITY
Arthropods
BIRDS
BREEDING
CROPS
Coleoptera
DIET
FEEDING
FOOD
FORESTS
HABITAT
HYMENOPTERA
LEAVES
SAVANNAH RIVER PLANT
SOUTH CAROLINA
TRAPPING
bird diets
crop flushing
migration
postbreeding