Gyrfalcon Diet in Central West Greenland During the Nesting Period

• Published in: The Condor
• Main Authors: Booms, Travis L., Fuller, Mark R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2003
• Subjects: Alopex lagopus; Arctic Fox; Arctic hare; Falco rusticolus; Greenland; Groenlandia; gyrfalcon; Lagopus mutus; Lepus arcticus; rock ptarmigan
• Online Access: http://dx.doi.org/10.1093/condor/105.3.528; http://academic.oup.com/condor/article-pdf/105/3/528/29712813/condor0528.pdf

Abstract We studied food habits of Gyrfalcons (Falco rusticolus) nesting in central west Greenland in 2000 and 2001 using three sources of data: time-lapse video (3 nests), prey remains (22 nests), and regurgitated pellets (19 nests). These sources provided different information describing the diet during the nesting period. Gyrfalcons relied heavily on Rock Ptarmigan (Lagopus mutus) and arctic hares (Lepus arcticus). Combined, these species contributed 79–91% of the total diet, depending on the data used. Passerines were the third most important group. Prey less common in the diet included waterfowl, arctic fox pups (Alopex lagopus), shorebirds, gulls, alcids, and falcons. All Rock Ptarmigan were adults, and all but one arctic hare were young of the year. Most passerines were fledglings. We observed two diet shifts, first from a preponderance of ptarmigan to hares in mid-June, and second to passerines in late June. The video-monitored Gyrfalcons consumed 94–110 kg of food per nest during the nestling period, higher than previously estimated. Using a combination of video, prey remains, and pellets was important to accurately document Gyrfalcon diet, and we strongly recommend using time-lapse video in future diet studies to identify biases in prey remains and pellet data. Dieta de Falco rusticolus durante el Período de Nidificación en el Centro-Oeste de Groenlandia Resumen. Estudiamos los hábitos alimenticios de Falco rusticolus durante la época de nidificación en el centro-oeste de Groenlandia durante los años 2000 y 2001. Utilizamos tres fuentes de datos: registros en lapsos de tiempo con cámaras de video (nidos en los árboles), restos de presas (22 nidos) y egagrópilas (19 nidos). Esto permitió describir la dieta durante el período de nidificación con base en la información diferente provista por cada fuente. F. rusticolus dependió fuertemente de las presas Lagopus mutus y Lepus arcticus. En forma combinada, estas dos especies contribuyeron en un 79–91% de la dieta total, dependiendo de los datos utilizados ...