Foraging ranges in Southern Rockhopper Penguins (Eudyptes chrysocome chrysocome) on Isla Noir, Chile

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
David Oehler ◽  
Danielle LaBruna ◽  
Manuel Marin ◽  
Alejandro Kusch ◽  
Leonard A Weakley ◽  
...  
Keyword(s):  
Foraging Ranges

scholarly journals Landscape structure affects the sunflower visiting frequency of insect pollinators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Károly Lajos ◽  
Ferenc Samu ◽  
Áron Domonkos Bihaly ◽  
Dávid Fülöp ◽  
Miklós Sárospataki
Keyword(s):  
Landscape Structure ◽  
Honey Bees ◽  
Agricultural Landscape ◽  
Edge Density ◽  
Wild Bees ◽  
Natural Habitats ◽  
Mass Flowering ◽  
Positive Effects ◽  
Pollinator Community ◽  
Foraging Ranges

AbstractMass-flowering crop monocultures, like sunflower, cannot harbour a permanent pollinator community. Their pollination is best secured if both managed honey bees and wild pollinators are present in the agricultural landscape. Semi-natural habitats are known to be the main foraging and nesting areas of wild pollinators, thus benefiting their populations, whereas crops flowering simultaneously may competitively dilute pollinator densities. In our study we asked how landscape structure affects major pollinator groups’ visiting frequency on 36 focal sunflower fields, hypothesising that herbaceous semi-natural (hSNH) and sunflower patches in the landscape neighbourhood will have a scale-dependent effect. We found that an increasing area and/or dispersion of hSNH areas enhanced the visitation of all pollinator groups. These positive effects were scale-dependent and corresponded well with the foraging ranges of the observed bee pollinators. In contrast, an increasing edge density of neighbouring sunflower fields resulted in considerably lower visiting frequencies of wild bees. Our results clearly indicate that the pollination of sunflower is dependent on the composition and configuration of the agricultural landscape. We conclude that an optimization of the pollination can be achieved if sufficient amount of hSNH areas with good dispersion are provided and mass flowering crops do not over-dominate the agricultural landscape.

Predation on marine-phase Atlantic salmon (Salmo salar) by gannets (Morus bassanus) in the Northwest Atlantic

2002 ◽  
Vol 59 (4) ◽  
pp. 602-612 ◽  
Author(s):  
W A Montevecchi ◽  
D K Cairns ◽  
R A Myers
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Labrador Sea ◽  
Atlantic Salmon Salmo Salar ◽  
Limited Sampling ◽  
Large Colony ◽  
Pelagic Food Webs ◽  
Migratory Routes ◽  
Pass Through ◽  
Foraging Ranges

Predation on Atlantic salmon (Salmo salar) has been recorded in rivers and estuaries, but there is little documentation of predation at sea. Prey landed by gannets (Morus bassanus) over 24 years in a large colony off northeast Newfoundland included small proportions of post-smolt Atlantic salmon. Before 1990, when shifts in oceanographic conditions and pelagic food webs occurred in the Labrador Sea, post-smolts, on average, made up 0.29% of estimated intake by gannets during August 1977–1989. In contrast, during the 1990s, this estimate increased to 2.53%, peaking at 6.37% in 1993. Model estimates with wide error margins projected that gannets consumed a mean of 1.6 t and 19.2 t of post-smolts during August 1977–1989 and 1990–2000, respectively, making up 0.22% and 2.70% of estimated North American post-smolt biomass during these periods. The migratory routes of post-smolt Atlantic salmon pass through the foraging ranges of gannet colonies, but limited sampling at colonies other than Funk has not revealed salmon in gannet diets. Sampling seabird diets is an economic, biological means of investigating the ecology and natural mortality of Atlantic salmon. Spatial and temporal expansion of this sampling would enhance its oceanographic context and reduce uncertainty associated with estimates of predation by seabirds.

Seabird foraging ranges as a preliminary tool for identifying candidate Marine Protected Areas

2012 ◽  
Vol 156 ◽  
pp. 53-61 ◽  
Author(s):  
Chris B. Thaxter ◽  
Ben Lascelles ◽  
Kate Sugar ◽  
Aonghais S.C.P. Cook ◽  
Staffan Roos ◽  
...  
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Foraging Ranges

The summer foraging ranges of adult spectacled petrels Procellaria conspicillata

2013 ◽  
Vol 26 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Tim A. Reid ◽  
Robert A. Ronconi ◽  
Richard J. Cuthbert ◽  
Peter G. Ryan
Keyword(s):  
South America ◽  
South Atlantic ◽  
Breeding Birds ◽  
Shelf Break ◽  
Fishing Activity ◽  
Breeding Grounds ◽  
Satellite Transmitters ◽  
Longline Fisheries ◽  
Central South ◽  
Foraging Ranges

AbstractSatellite transmitters were attached to eight adult spectacled petrels Procellaria conspicillata Gould captured during the early incubation period at their breeding grounds on Inaccessible Island, one of the Tristan da Cunha Islands in the central South Atlantic Ocean. Data on their at-sea distribution was obtained for up to six months. All birds remained within the South Atlantic from 24–44°S, with most between 25 and 40°S. Breeding birds mainly foraged in oceanic waters, but failed breeders or non-breeders concentrated their foraging activity over the Rio Grande Rise and the Walvis Ridge and along the shelf break off the east coast of South America. Little foraging occurred along the Benguela shelf break off southern Africa. Non-breeders favoured relatively warm water with low chlorophyll concentrations, reducing the risk of bycatch in fisheries. Tracked birds spent 16% of their time in areas with high levels of tuna longline fishing activity, with overlap greater for non-breeding birds (22%) than breeding birds (3%). Birds in this study foraged in shallower waters along the continental shelf edge off South America than spectacled petrels tracked in this area in winter, potentially increasing their risk of exposure to demersal longline fisheries in this area in summer.

scholarly journals Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird

2015 ◽  
Vol 2 (4) ◽  
pp. 140291 ◽  
Author(s):  
Nicole D. Kowalczyk ◽  
André Chiaradia ◽  
Tiana J. Preston ◽  
Richard D. Reina
Keyword(s):  
Prey Availability ◽  
Juvenile Fish ◽  
Fish Communities ◽  
Small Range ◽  
Isotopic Niche ◽  
Fine Scale ◽  
Close Proximity ◽  
Isotope Analyses ◽  
Little Penguin ◽  
Foraging Ranges

Unlike migratory seabirds with wide foraging ranges, resident seabirds forage in a relatively small range year-round and are thus particularly vulnerable to local shifts in prey availability. In order to manage their populations effectively, it is necessary to identify their key prey across and within years. Here, stomach content and stable isotope analyses were used to reconstruct the diet and isotopic niche of the little penguin ( Eudyptula minor ). Across years, the diet of penguins was dominated by anchovy ( Engraulis australis ). Within years, during winter, penguins were consistently enriched in δ 15 N and δ 13 C levels relative to pre-moult penguins. This was probably due to their increased reliance on juvenile anchovies, which dominate prey biomass in winter months. Following winter and during breeding, the δ 13 C values of penguins declined. We suggest this subtle shift was in response to the increased consumption of prey that enter the bay from offshore regions to spawn. Our findings highlight that penguins have access to both juvenile fish communities and spawning migrants across the year, enabling these seabirds to remain in close proximity to their colony. However, annual fluctuations in penguin isotopic niche suggest that the recruitment success and abundance of fish communities fluctuate dramatically between years. As such, the continued monitoring of penguin diet will be central to their ongoing management.

At-sea movements and habitat use of adult male Australian fur seals (Arctocephalus pusillus doriferus)

2006 ◽  
Vol 84 (12) ◽  
pp. 1781-1788 ◽  
Author(s):  
Roger Kirkwood ◽  
Michael Lynch ◽  
Nick Gales ◽  
Peter Dann ◽  
Michael Sumner
Keyword(s):  
Habitat Use ◽  
Continental Shelf ◽  
Adult Male ◽  
Maximum Distance ◽  
Commercial Fisheries ◽  
Southeastern Australia ◽  
Foraging Area ◽  
Fur Seals ◽  
Water Columns ◽  
Foraging Ranges

Foraging by adult male otariids, a demographic component that often interacts with commercial fisheries, are poorly known. To assess movement patterns and habitat use, nine adult male Australian fur seals ( Arctocephalus pusillus doriferus Wood Jones, 1925) from Seal Rocks, in northern Bass Strait, southeastern Australia, were tracked for periods ranging from 66 to 223 d during 1999–2001. Mean ± SD at-sea and on-land durations were 6.9 ± 2.1 d (range 2.3–10.3 d, n = 9 seals) and 2.4 ± 0.9 d (range 0.8–4.1 d), respectively. All seals foraged almost exclusively in continental shelf waters and mostly (65%–97% of time at sea) in water columns that were between 40 and 100 m deep. Six of nine seals tracked for >30 d spent 64%–98% of their time-at-sea foraging at distances <200 km from Seal Rocks, although the maximum distance achieved from the colony was 1208 km. The seals’ foraging ranges overlapped with the ranges of operation of virtually all fin-fish fisheries in southeastern Australia, but fisheries overlap was low in the most frequented foraging area of central-western Bass Strait.

Foraging ranges of penguins

Polar Record ◽  
1989 ◽  
Vol 25 (155) ◽  
pp. 303-308 ◽  
Author(s):  
Rory P. Wilson ◽  
Ken A. Nagy ◽  
Bryan S. Obst
Keyword(s):  
Simple Model ◽  
Range Limits ◽  
Published Data ◽  
Pygoscelis Adeliae ◽  
Model Based ◽  
Foraging Ranges

abstractSpeed/distance meters were deployed on adeliée, gentoo and chinstrap penguinsPygoscelis adeliae, P. papua and P. antarctica, breeding near Anvers Island, Antarctica. Underwater speeds and distances travelled were interspecifically very similar (means of ca. 7–8 km h-1and 15–45 km, respectively). These results are compared with published data on penguin behaviour at sea obtained by using identical methodology. A simple model, based on penguin activity at sea data, is developed to derive range limits for penguins. Derived range limits are substantially lower than previous estimates but accord well with distributional data obtained by transects.

Estimated food consumption by penguins at the Prince Edward Islands

1993 ◽  
Vol 5 (3) ◽  
pp. 245-252 ◽  
Author(s):  
N. J. Adams ◽  
C. Moloney ◽  
R. Navarro
Keyword(s):  
Food Consumption ◽  
Demersal Fish ◽  
Pelagic Fish ◽  
Total Consumption ◽  
Transfer Rates ◽  
Prince Edward Islands ◽  
Important Prey ◽  
Seasonal Basis ◽  
Myctophid Fish ◽  
Foraging Ranges

The consumption of food by the four species of breeding penguins at the Prince Edward Islands is assessed on an annual and seasonal basis. Total annual food consumption was estimated at 880 000 t, of which king penguins accounted for 74%, macaroni penguins 21%, rockhopper penguins 5% and gentoo penguins <1%. Pelagic fish, almost entirely myctophids, were the most important prey (70% of total prey biomass), followed by pelagic crustaceans (18%) and cephalopods (11%). Demersal fish and benthic crustaceans accounted for <1% of total consumption, being consumed only by gentoo penguins. Peak demands of between 2 and 3.3 × 106 kg d−1 occurred from October–December when three of the four species were breeding, including the two demi-populations of king penguins. Food demand decreased to 1.2 × 106 kg d−1 during winter when only king and gentoo penguins were present. Much of the prey are presumably captured within 300 km of the islands. Assuming an even distribution of foraging effort within their respective foraging ranges, rates of food transferred to penguins in November ranged from 4.1 × 10−3 g m−2 d−1 for macaroni penguins to 1.24 × 10−2 g m−2 d−1 for king penguins. In mid-July, transfer rates to king and gentoo penguins were 3.9 × 10−3 g m−2 d−1 and 6.7 × 10−3 g m−2 d−1, respectively. The importance of pelagic myctophid fish to penguin populations at the Prince Edward Islands is clear.

Vertical stratification of fruit bats (Pteropodidae) in lowland dipterocarp rainforest in Malaysia

1994 ◽  
Vol 10 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Charles M. Francis
Keyword(s):  
Seed Dispersal ◽  
Forest Regeneration ◽  
Food Selection ◽  
Ground Level ◽  
Peninsular Malaysia ◽  
Forest Trees ◽  
Fruit Bats ◽  
Lowland Rainforest ◽  
Capture Rates ◽  
Foraging Ranges

ABSTRACTMistnets were set at ground level and 11–30 m above ground in lowland rainforest at Kuala Lompat in peninsular Malaysia, and Sepilok in Sabah, to compare the abundance of fruit bats in the subcanopy and at ground level. Capture rates in the subcanopy were up to 100 times greater than at ground level, averaging 3–7 bats per net-night. Species diversity was higher in the subcanopy than forest understorey. Two species that were frequently captured in the subcanopy,Megaerops wetmoreiandDyacopterus spadiceus, were previously thought to be rare. The abundance of Old World fruit bats in the subcanopy indicates that their roles in pollination and seed dispersal of Malaysian forest trees may be greater than previously recognized. Further research on foraging ranges, food selection and roosting habits is required to determine the overall importance of fruit bats in forest regeneration through seed dispersal, and the adequacy of existing reserves for their conservation.

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