scholarly journals Linking predator diet and prey availability: common murres and capelin in the Northwest Atlantic

2012 ◽  
Vol 445 ◽  
pp. 25-35 ◽  
Author(s):  
AD Buren ◽  
M Koen-Alonso ◽  
WA Montevecchi
Keyword(s):  
Prey Availability ◽  
Northwest Atlantic ◽  
Predator Diet ◽  
Common Murres

Inter-colony foraging dynamics and breeding success relate to prey availability in a pursuit-diving seabird

2020 ◽  
Vol 651 ◽  
pp. 183-198
Author(s):  
J Gulka ◽  
E Jenkins ◽  
LD Maynard ◽  
WA Montevecchi ◽  
PM Regular ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Prey Availability ◽  
Anthropogenic Pressures ◽  
Niche Dynamics ◽  
Common Murres ◽  
Distribution Of Resources ◽  
Foraging Niche ◽  
And Behavior ◽  
Foraging Distances ◽  
Adult Diet

Spatial patterns of breeding seabirds are influenced by the distribution of resources in relation to the colony and the density of conspecifics from the same or adjacent colonies. We conducted an inter-colony comparison of foraging space use and behavior, diet, and reproductive success of common murres Uria aalge breeding at a large offshore and a small inshore colony on the northeastern coast of Newfoundland (Canada) during 2016-2018 under varying prey (capelin Mallotus villosus) biomass. Murres from the large offshore colony foraged over a greater area, with greater individual foraging distances, indicative of higher commuting costs compared to the smaller inshore colony. Although this pattern might reflect prey depletion near the offshore colony due to higher conspecific densities, it likely also reflects the greater distance to predictable, high-abundance prey aggregations. This is supported by high spatial overlap of foraging areas from both colonies near coastal, annually persistent capelin spawning sites. Adult diet was similar between colonies during incubation, but diverged during chick-rearing, with offshore murres consuming a higher proportion of alternative prey, while inshore murres consumed more capelin. These differences did not affect fledging success, although hatching success was lower in the larger colony, suggesting that divergent factors (e.g. predation, nest attendance) influence colony-specific population dynamics. Overall, our findings suggest that abundant local prey is key in shaping spatial patterns of breeding common murres in northeastern Newfoundland and results in apparently minimal intraspecific competition. As anthropogenic pressures on resource availability heighten, insight into factors influencing intraspecific foraging niche dynamics will be critical to inform management.

Recent changes in the winter diet of murres (Uria spp.) in coastal Newfoundland waters

2000 ◽  
Vol 78 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Sherrylynn Rowe ◽  
Ian L Jones ◽  
John W Chardine ◽  
Richard D Elliot ◽  
Brian G Veitch
Keyword(s):  
Marine Organisms ◽  
Frequency Of Occurrence ◽  
Boreogadus Saida ◽  
Sources Of Information ◽  
Uria Lomvia ◽  
Northwest Atlantic ◽  
Winter Diet ◽  
Ecological Changes ◽  
Common Murres ◽  
Capelin Mallotus Villosus

We investigated the winter diet of murres (Uria spp.) in coastal Newfoundland waters in relation to environmental and ecological changes that have occurred in the Northwest Atlantic since the 1980s. We analyzed the contents of 371 stomachs (311 from Thick-billed Murres, Uria lomvia, and 60 from Common Murres, Uria aalge) of birds shot by hunters around the Newfoundland coast during the winters of 1996-1998. We observed that the frequency of empty stomachs was greater in our study than in a similar study conducted during 1984-1986. We found no difference in the proportion of fish in the diet between the 1980s and the 1990s, however, Arctic cod (Boreogadus saida; from 55 to 12%) and capelin (Mallotus villosus; from 28 to 6%) decreased in frequency of occurrence. The proportion of stomachs containing crustaceans and squid did not change between the 1980s and 1990s, but hyperiid amphipods (Parathemisto spp.) replaced euphausiids (Thysanoessa spp.) as the predominant crustacean. Changes in murre winter diet off the coast of Newfoundland corroborate other sources of information indicating that major changes in the distribution and biology of marine organisms occurred in the Northwest Atlantic during the 1990s.

scholarly journals Activity Budgets and Foraging Ranges of Breeding Common Murres

The Auk ◽  
1987 ◽  
Vol 104 (2) ◽  
pp. 218-224 ◽  
Author(s):  
D. K. Cairns ◽  
K. A. Bredin ◽  
W. A. Montevecchi
Keyword(s):  
Foraging Ecology ◽  
Prey Availability ◽  
Flight Time ◽  
Trip Duration ◽  
Time Budgets ◽  
Common Murres ◽  
Electronic Activity ◽  
Incubating Birds ◽  
Time Away ◽  
Foraging Ranges

Abstract We used electronic activity recorders to measure flight time, dive time, and time on the water of breeding Common Murres (Uria aalge). During both incubation and chick rearing, about 90% of birds' time away from the colony was spent on the water or diving and 10% was spent flying. The proportion of flight time did not vary with trip duration. During chick rearing, 13.6% of time away from the colony was spent diving, and the proportion of time spent diving tended to decrease with trip duration. Potential foraging ranges calculated from flight times during individual foraging trips showed a concave frequency distribution, and median potential ranges were 37.8 km for incubating birds and 5.4 km for chick-rearing birds. The use of electronic recorders to measure time budgets has broad applications for seabird energetics and foraging ecology and for the assessment of prey availability and abundance.

Responses to changes in prey availability by Common Murres and Thick-billed Murres at the Gannet Islands, Labrador

1999 ◽  
Vol 77 (8) ◽  
pp. 1278-1287 ◽  
Author(s):  
Rachel Bryant ◽  
Ian L Jones ◽  
J Mark Hipfner
Keyword(s):  
Breeding Success ◽  
Prey Availability ◽  
Feeding Rates ◽  
Chick Growth ◽  
Uria Lomvia ◽  
Foraging Effort ◽  
Common Murre ◽  
Common Murres ◽  
Capelin Mallotus Villosus ◽  
Adult Mass

We quantified Common Murre (Uria aalge) and Thick-billed (Uria lomvia) Murre chick diets, chick-feeding rates, breeding success, chick growth, adult masses, and pair members' time spent together at site at the Gannet Islands, Labrador, in 1996 and 1997, after a decline in capelin (Mallotus villosus) abundance along the coast of southern and central Labrador. These results, with the exception of time spent at the site, were compared with those collected by other researchers at the Gannet Islands in 1981-1983, before the capelin decline. The two species responded similarly to the decline. After the decline, murres fed their chicks up to 75% fewer capelin and up to 65% more daubed shannies (Lumpenus maculatus). Feeding rates of both murre species varied among years, without respect to changes in the proportion of capelin. We found no evidence for declines in colony attendance, breeding success, chick growth, and adult mass. No data on time spent at the site were available before the decline in capelin abundance, but after the decline, off-duty murres of both species spent a mean of 10 min at their sites per feeding visit. This amount of time was short with respect to that recorded for Common Murres elsewhere, suggesting that murres' foraging effort at the Gannet Islands was high and buffered the effects of prey availability on other parameters measured. Taken together, our results suggest that murres responded to changing capelin abundance by changing their chicks' diet, but were otherwise little affected.

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