Skip to Main Content
Food habits of Bald Eagles breeding in the Arizona desertAuthor(s): Teryl G. Grubb
Source: Wilson Bulletin. 107(2): 258-274.
Publication Series: Scientific Journal (JRNL)
PDF: View PDF (983.55 KB)
DescriptionOf 1814 foraging attempts, prey captures, or nest deliveries by Bald Eagles (Haliaeetus leucocephalus) in 14 Arizona breeding areas during 1983-1985, 1471 observations were identifiable to at least class: fish (76%), mammal (18%), bird (4%), and reptile/amphibian (2%). Forty-five species were recorded: catfish (Ictalurus punctatus, Pylodictis olivaris), suckers (Catostomus insignis, C. clarki), and carp (Cyprinus carpio) were most common. Mean population dietary heterogeneity was 2.03 (SD = 0.43). During 1983-1985, 22 successful sites had a wider dietary breadth than nine unsuccessful ones (3.73 vs 1.92). Fish and mammal classes varied by month (P < 0.001) and breeding area (P < 0.001) and were negatively correlated (R = -0.993, P = 0.001). Of 484 discrete foraging locations, only four (<1%) were frequented in more than one year. Within-season shifts in foraging locations were typical within breeding areas to accommodate changing prey availability. Foraging activity varied hourly and among prey classes, peaking 08:00-10:00 and 16:00-19:00 h MST (P < 0.001). Perches east (NE-E-SE) of foraging sites were used more often before 13:00 h MST (59.3%, N = 118), while perches west (SW-W-NW) were used more often after 13:00 h (58.4%, N = 113; P = 0.013). Most foraging occurred near shore in shallow river waters. The mean straight-line distance between Verde River nest sites was 14.4 km (SD = 3.5) with a ratio of river: straight-line distance of 1.4: 1. Opportunistic and breeding area-specific foraging was evident throughout the population.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationGrubb, Teryl G. 1995. Food habits of Bald Eagles breeding in the Arizona desert. Wilson Bulletin. 107(2): 258-274.
KeywordsBald Eagles, Haliaeetus leucocephalus, breeding, foraging, Arizona
- Hydrologic habitat preferences of select southeastern USA fishes resilient to river ecosystem fragmentation
- Intersexual variation in the foraging ecology of sexually monochromatic Western Wood-Pewees
- Host fishes and infection strategies of freshwater mussels in large Mobile Basin streams, USA
XML: View XML