Spatio-temporal patterns of foraging behaviour in a wide-ranging seabird reveal the role of primary productivity in locating prey

2020 ◽  
Vol 646 ◽  
pp. 175-188
Author(s):  
A Kane ◽  
E Pirotta ◽  
S Wischnewski ◽  
EJ Critchley ◽  
A Bennison ◽  
...  

Predicting the distribution and behaviour of animals is a fundamental objective in ecology and a cornerstone of conservation biology. Modelling the distribution of ocean-faring species like seabirds remains a significant challenge due to ocean dynamics, colony-specific effects and the vast ranges seabirds can cover. We used a spatial and behavioural approach to model the distribution of the Manx shearwater Puffinus puffinus, a pelagic, central-place forager that can cover great distances while foraging. GPS data from birds tagged in 2 colonies over 3 yr were modelled with a range of environmental predictors of marine productivity. For both colonies, transitions to foraging behaviour correlated with chlorophyll a, and the distribution of foraging behaviour was also associated with areas of high chlorophyll a concentration in coastal but not offshore areas for one colony. Furthermore, there was evidence for colony differences in habitat use, prevalence of nocturnal foraging, and for some competitive exclusion on foraging grounds, even though the colonies were 170 km apart. Despite the extensive dataset, our models had modest predictive power, which we suggest can probably only be improved by including biotic interactions, including more direct measures of food resource distribution. Our results highlight the importance of including spatial complexity and data from multiple sites when predicting the distribution of wide-ranging predators, because patterns of distribution and habitat use likely differ across the range of a population.

1990 ◽  
Vol 68 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Chris E. Beers ◽  
Joseph M. Culp

Unlike most cyprinids, the longnose dace (Rhinichthys cataractae) forages primarily at night in streams in southern Alberta. This nocturnal strategy may result from intrinsic capabilities, like dark-adapted vision, or extrinsic constraints due to biotic interactions during the day. Our objectives were to determine, in the absence of biotic interactions such as predation and competition, (i) whether this foraging habit maximized the foraging ability of the dace in terms of search time, reaction distance, and attack efficiency; and (ii) if dace foraging behaviour was sufficiently plastic to adjust to changes in light intensity. All measures of foraging ability were superior under twilight conditions. Although search times in starlight were double those in twilight, this increase was much smaller than was predicted using a hemispherical search volume model. The daces' ability to offset small nocturnal search volumes was accomplished by changing their pattern of search behaviour. In particular, use of a benthic rooting behaviour increased, and we hypothesize that this behaviour is associated with location of prey by olfaction. Although the nocturnal foraging strategy of dace does not appear to maximize net energy gain, this strategy may be a response to other constraints, such as high predation risk during diel periods with increased illumination.


2004 ◽  
Vol 82 (6) ◽  
pp. 922-933 ◽  
Author(s):  
D Gallant ◽  
C H Bérubé ◽  
E Tremblay ◽  
L Vasseur

The objective of this study was to examine the foraging behaviour of the beaver (Castor canadensis Kuhl, 1820) and to explain its selection of terrestrial woody plant species according to central place foraging theory. Limitations in variety of food items in most studies with regard to size and (or) distance from the central place and information on availability of forage choices give a partial view of the subject. In this study, the theory is tested in a natural environment with high variability in food items with regard to these factors. Foraging choices by beavers were inspected by measuring variables on cut and uncut trees of every species encountered within 1 m of trail systems made by 25 beaver colonies in Kouchibouguac National Park in New Brunswick, Canada, thereby quantifying the availability of the different food items. The effect of habitat quality (food availability) on the foraging behaviour of beavers was also tested. The results of this study suggest that with increasing distance from the pond, beavers in high-quality habitats selected fewer, but larger, trees and are more species selective. This selectivity was diminished in habitats of lower quality. The results of this study are consistent with the predictions of the central foraging theory.


2014 ◽  
Vol 281 (1778) ◽  
pp. 20132883 ◽  
Author(s):  
Ewan D. Wakefield ◽  
Richard A. Phillips ◽  
Jason Matthiopoulos

Animal populations are frequently limited by the availability of food or of habitat. In central-place foragers, the cost of accessing these resources is distance-dependent rather than uniform in space. However, in seabirds, a widely studied exemplar of this paradigm, empirical population models have hitherto ignored this cost. In part, this is because non-independence among colonies makes it difficult to define population units. Here, we model the effects of both resource availability and accessibility on populations of a wide-ranging, pelagic seabird, the black-browed albatross Thalassarche melanophris . Adopting a multi-scale approach, we define regional populations objectively as spatial clusters of colonies. We consider two readily quantifiable proxies of resource availability: the extent of neritic waters (the preferred foraging habitat) and net primary production (NPP). We show that the size of regional albatross populations has a strong dependence, after weighting for accessibility, on habitat availability and to a lesser extent, NPP. Our results provide indirect support for the hypothesis that seabird populations are regulated from the bottom-up by food availability during the breeding season, and also suggest that the spatio-temporal predictability of food may be limiting. Moreover, we demonstrate a straightforward, widely applicable method for estimating resource limitation in populations of central-place foragers.


2016 ◽  
Vol 3 (5) ◽  
pp. 160043 ◽  
Author(s):  
Ari S. Friedlaender ◽  
David W. Johnston ◽  
Reny B. Tyson ◽  
Amanda Kaltenberg ◽  
Jeremy A. Goldbogen ◽  
...  

Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator–prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager studies.


2001 ◽  
Vol 28 (4) ◽  
pp. 365 ◽  
Author(s):  
Tom Aumann

On the basis of opportunistic observations, the preferred habitats of diurnal raptors in the south-west of the Northern Territory are quantified in terms of their vegetation structures and composition, and linked with foraging methods and information on local diets. Broad interspecific differences in diel activity patterns are also described. The evidence suggests that raptor species in this part of arid Australia differ with respect to their foraging times, habitats and methods, and that these differences relate to their partitioning of food resources.


2016 ◽  
Vol 98 (5) ◽  
pp. 1081-1086 ◽  
Author(s):  
Israel S. Maciel ◽  
Rodrigo H. Tardin ◽  
Sheila M. Simão

Ninety-six field trips were conducted between summer 2010 and 2012 in order to understand the occurrence and habitat use of Bryde's whale (Balaenoptera edeni) in the Cabo Frio region, South-eastern Brazil. Bryde's whales were present in the study area between November and July, being observed during all seasons, but occur more frequently during the autumn (Nindividuals = 16) and spring (Nindividuals = 13), followed by summer (Nindividuals = 5) and winter (Nindividuals = 2), respectively. Bryde's whales were observed in water depths ranging from 20.1–100 m. Furthermore, during 2240 min of video recordings, the most frequent behaviour observed was foraging (40.2%; 900 min). Travelling comprised 28.1% (630 min) of observations, while in 33.1% (710 min) behaviour could not be determined. Taking into account the pattern of occurrence, the use of deeper bathymetric bins and the frequency observed, the foraging behaviour of Bryde's whales observed in our study seems to be associated to prey dynamics. Our data show that the study area is frequently used for foraging by this species in Brazilian waters.


2020 ◽  
Vol 7 (5) ◽  
pp. 181423
Author(s):  
Marlenne A. Rodríguez-Malagón ◽  
Elodie C. M. Camprasse ◽  
Lauren P. Angel ◽  
John P. Y. Arnould

Foraging is a behaviour that can be influenced by multiple factors and is highly plastic. Recent studies have shown consistency in individual foraging behaviour has serious ecological and evolutionary implications within species and populations. Such information is crucial to understand how species select habitats, and how such selection might allow them to adapt to the environmental changes they face. Five foraging metrics (maximum distance from the colony, bearing from the colony to the most distal point, tortuosity index, total number of dives and mean vectorial dynamic body acceleration were obtained using GPS tracking and accelerometry data in adult Australasian gannets ( Morus serrator ) from two colonies in southeastern Australia. Individuals were instrumented over two breeding seasons to obtain data to assess factors influencing foraging behaviour and behavioural consistency over multiple timescales (consecutive trips, breeding stages and years) and habitats (pelagic, mixed pelagic and inshore, and inshore). Colony, breeding stage and year were the factors which had the greatest influence on foraging behaviour, followed by sex. Behavioural consistency, measured as the contribution of the individual to the observed variance, was low to moderate for all foraging metrics (0.0–27.05%), with the higher values occurring over shorter timescales. In addition, behavioural consistency was driven by spatio-temporal factors rather than intrinsic characteristics. Behavioural consistency was higher in individuals foraging in inshore than pelagic habitats or mixed pelagic/inshore strategy, supporting suggestions that consistency is favoured in stable environments.


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