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Research about Semidi Islands

Source-linked reports with geographic coverage including Semidi Islands.

7 recordsLinked to original sources
USGS2008

Incubation rhythm in the Fulmar Fulmarus glacialis : Annual variation and sex roles

I monitored the incubation schedules of Fulmars Fulmarus glacialis in an Alaskan colony by observing nests where the male and female were of different colour phases. Complete shifts of up to 16 days were recorded; the average shift in mid-incubation was 4–6 days. Mean shift length was inversely correlated with hatching success in 5 years, suggesting that Fulmars adjusted their foraging patterns to annual differences in food availability. Males assumed the larger share (55%) of incubation on average, and a larger share in years with lower hatching success. Serial correlation in the length of incubation shifts had two components - the influence of prior shift lengths on time spent foraging and individual variation. Failure of the male to relieve the female soon after laying resulted in a few breeding failures and egg losses were associated with exceptionally long shifts throughout incubation.

Alaska↗
USGS2002

Activity patterns and monitoring numbers of Horned Puffins and Parakeet Auklets

Nearshore counts of birds on the water and time-lapse photography were used to monitor seasonal activity patterns and interannual variation in numbers of Horned Puffins ( Fratercula corniculata ) and Parakeet Auklets ( Aethia psittacula ) at the Semidi Islands, Alaska. The best period for over-water counts was mid egg-laying through hatching in auklets and late prelaying through early hatching in puffins. Daily counts (07.00 h-09.30 h) varied widely, with peak numbers and days with few or no birds present occurring throughout the census period. Variation among annual means in four years amounted to 26% and 72% of total count variation in puffins and auklets, respectively. Time-lapse photography of nesting habitat in early incubation revealed a morning (08.00 h-12.00 h) peak in the number of puffins loitering on study plots. Birds recorded in time-lapse images never comprised more than a third of the estimated breeding population on a plot. Components of variance in the time-lapse study were 29% within hours, 9% among hours (08.00 h-12.00 h), and 62% among days (8-29 June). Variability of over-water and land-based counts is reduced by standardizing the time of day when counts are made, but weather conditions had little influence on either type of count. High interannual variation of population indices implies low power to detect numerical trends in crevice-nesting auklets and puffins.

Alaska↗
USGS1990

Time allocation by northern fulmars during the breeding season

Averaged over the whole breeding cycle (pre-laying through mid-chick stage), breeding fulmars spent about 39% of their time at the breeding site and 61% of their time at sea. Annual means of site occupancy before egg-laying were positively correlated with breeding success, suggesting that time allocation was a sensitive indicator of food availability in different years. Nonbreeding site-holders spent about half as much time at the colony as breeders; their attendance was highest early in the season when pair bonds and site ownership were established. The attendance of failed birds after egg or chick loss was positively correlated with colony-wide breeding success in six years. Males spent more time at the breeding site than females at every stage of the season. Most days were devoted to foraging in the pre-laying period (69% in males, 82% in females). An extended absence from the colony just before laying (the pre-laying exodus) averaged 12.2 d in males and 17.6 d in females. Changes in body weight indicated that neither sex incurred an energy deficit on a seasonal basis. A greater investment by the male in site attendance during incubation offset the female's investment in egg production and assured that both sexes entered the demanding chick-feeding stage in good condition.

Alaska↗
USGS1990

Individual variation in behavior and breeding success of Northern Fulmars

In a sample of breeding Northern Fulmars ( Fulmarus glacialis ) observed in 4-5 years, up to 43% of the variability in 13 attributes of breeding behavior was consistent among individuals or pairs. Sample means for most attributes were correlated in a predictable way with annual levels of breeding success. Except for laying dates, there was little evidence that individual differences in these attributes contributed to variation in breeding success. A test of breeding experience as a contributing factor revealed an interaction between individual and annual components of variation. During years when the whole population did relatively poorly, pairs with no previous breeding experience were affected disproportionately. Late-nesting fulmars were more successful than early layers, possibly because delayed breeding ensured that food availability was adequate for successful incubation.

Alaska↗
USGS1987

Copulation and mate guarding in the Northern Fulmar

I studied the timing and frequency of copulation in mated pairs and the occurrence of extra-pair copulation (EPC) among Northern Fulmars ( Fulmarus glacialis ) for 2 yr. Copulation peaked 24 days before laying, a few days before females departed on a prelaying exodus of about 3 weeks. I estimated that females were inseminated at least 34 times each season. A total of 44 EPC attempts was seen, 9 (20%) of which apparently resulted in insemination. Five successful EPCs were solicitated by females visiting neighboring males. Multiple copulations during a single mounting were rare within pairs but occurred in nearly half of the successful EPCs. Both sexes visited neighbors during the prelaying period, and males employed a special behavioral display to gain acceptance by unattended females. Males invested time in nest-site attendance during the prelaying period to guard their mates and pursue EPC. However, the occurrence of EPC in fulmars was largely a matter of female choice.

Alaska↗
USGS1983

Mechanism and ecological significance of sperm storage in the Northern Fulmar with reference to its occurrence in other birds

Sperm-storage glands were found in the uterovaginal (UV) region of the oviduct in Northern Fulmars ( Fulmarus glacialis ), Horned Puffins ( Fratercula corniculata ), and Leach's Storm-Petrels ( Oceanodroma leucorhoa ) collected before or shortly after egg laying. Previously described only in domestic Galliformes, UV sperm-storage glands may prove to be a common feature of the avian reproductive system. There is as yet no compelling explanation of their function in the Horned Puffin. In the Northern Fulmar, and probably in other petrels, however, sperm-storage glands allow the separation of the male and female over pelagic waters for several weeks immediately before egg laying. The likelihood of prolonged viability of sperm in the female reproductive tract should be considered in interpreting the sexual behavior of other wild birds.

Alaska↗