Geology topics

Travis Booms

Publications and source records attributed to Travis Booms.

3 recordsLinked to original sources

USGS2003

Gyrfalcon feeding behavior during the nestling period in central west Greenland

We studied gyrfalcon ( Falco rusticolus ) food delivery and feeding behavior during the nestling period in central West Greenland during the 2000 and 2001 field seasons. We used time-lapse video cameras installed at three nests to record 2677.25 hours of nestling video. Ptarmigan delivered to nests were usually plucked prior to delivery and included the breast and superior thoracic vertebrae. Arctic hare leverets were rarely plucked and often delivered in parts. The most commonly delivered leveret part was the hind legs attached to the lower back. Passerines were rarely plucked and usually delivered whole. After feeding the young, adults removed 20.9% of prey items from the nest, which included items both with and without obvious muscle still attached. Prey delivery rates were similar among nests and increased as nestlings aged. Prey delivery frequency peaked in the morning and evening, with a distinct lull in the late evening and early morning hours. Male and female adults delivered a similar number of prey, though males typically delivered smaller prey than females. Gyrfalcons cached and re-delivered at least 9.1% of all items delivered, and one item was cached and retrieved three times.

Arctic↗

USGS2003

Time-lapse video sysem used to study nesting Gyrfalcons

We used solar-powered time-lapse video photography to document nesting Gyrfalcon ( Falco rusticolus ) food habits in central West Greenland from May to July in 2000 and 2001. We collected 2677.25 h of videotape from three nests, representing 94, 87, and 49% of the nestling period at each nest. The video recorded 921 deliveries of 832 prey items. We placed 95% of the items into prey categories. The image quality was good but did not reveal enough detail to identify most passerines to species. We found no evidence that Gyrfalcons were negatively affected by the video system after the initial camera set-up. The video system experienced some mechanical problems but proved reliable. The system likely can be used to effectively document the food habits and nesting behavior of other birds, especially those delivering large prey to a nest or other frequently used site.

Kangerlussuaq↗

USGS2003

Gyrfalcon diet in central west Greenland during the nestling period

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.

The Condor↗