scholarly journals Foraging behaviour of American oystercatchers in response to declining prey densities

1997 ◽  
Vol 75 (2) ◽  
pp. 170-181 ◽  
Author(s):  
Joanne Tuckwell ◽  
Erica Nol
Keyword(s):  
Crassostrea Virginica ◽  
Seasonal Changes ◽  
Prey Density ◽  
Foraging Behaviour ◽  
Niche Breadth ◽  
Time Budgets ◽  
Behavioural Flexibility ◽  
Close Match ◽  
Commercial Harvest ◽  
Haematopus Palliatus

American oystercatchers (Haematopus palliatus) responded to declines in the density of oysters (Crassostrea virginica) on a commercial oyster bed examined in 1979 and 1995 by increasing the number of species of prey eaten and search times, but not peck rates or handling times. Seasonal changes in foraging behaviour included oystercatchers choosing larger oysters with longer handling times in winter than in autumn, but with subsequently greater profitability and higher intake rates. Time budgets of foraging birds were similar in the two seasons. Oystercatchers ate fewer mussels in winter than in autumn, and fewer mussels than oysters at all times. Search and handling times for mussels were similar in autumn of the 2 years. After a commercial harvest of oysters at a second site, handling times for oysters did not decline; however, search times were significantly more variable, niche breadth was greater, and there was a trend towards longer search times post harvest. The recorded changes in foraging behaviour indicated a close match between search and handling times and prey density and size and behavioural flexibility of foraging birds in response to sometimes drastic changes in their prey base.

scholarly journals A comparison of morphology and web geometry between hypogean and epigean species of Metellina orb spiders (family Tetragnathidae)

2019 ◽  
Vol 32 ◽  
pp. 1-13 ◽  
Author(s):  
Thomas Hesselberg ◽  
Daniel Simonsen
Keyword(s):  
Life Style ◽  
Foraging Behaviour ◽  
Behavioural Flexibility ◽  
Permanent Record ◽  
Behavioural Adaptation ◽  
Web Geometry ◽  
Web Building

Studies on the behaviour of subterranean animals are rare, mainly due to the problems with collecting data in these inaccessible habitats. Web-building cave spiders, however, leave a semi-permanent record of their foraging behaviour, which can relatively easily be recorded. In this study, we compare size, leg lengths and web characteristics between hypogean populations of Metellina merianae with its close wood-inhabiting relative M. mengei. We confirm previous observations that M. merianae does not show any obvious morphological and behavioural adaptions to a subterranean life-style, although individuals of the cave species were significantly larger and had webs with relatively fewer radii and capture spiral turns than M. mengei. We were, however, not able to determine if these findings indicate a transition towards behavioural adaptation to caves or if they are a result of behavioural flexibility in response to the different humidity and temperature between caves and woodland. Finally, we did not find any effect of cave characteristics on either the number of radii or the area of the M. merianae web.

scholarly journals Linking social foraging behaviour with individual time budgets and emergent group-level phenomena

2012 ◽  
Vol 84 (6) ◽  
pp. 1295-1305 ◽  
Author(s):  
Harry H. Marshall ◽  
Alecia J. Carter ◽  
J. Marcus Rowcliffe ◽  
Guy Cowlishaw
Keyword(s):  
Foraging Behaviour ◽  
Social Foraging ◽  
Group Level ◽  
Time Budgets

Foraging habitat selection by American and Magellanic oystercatchers (Haematopus palliatus and H. leucopodus) on Patagonian tidal flats

1991 ◽  
Vol 69 (6) ◽  
pp. 1636-1643 ◽  
Author(s):  
Douglas Siegel-Causey
Keyword(s):  
Wind Speed ◽  
Foraging Behavior ◽  
Foraging Behaviour ◽  
Abiotic Factors ◽  
Species Abundance ◽  
Tidal Flats ◽  
Foraging Habitat ◽  
Loglinear Models ◽  
Tidal State ◽  
Haematopus Palliatus

I examined the foraging behaviour of American and Magellanic oystercatchers on Patagonian tidal flats in the context of several abiotic and social factors. I analyzed the simultaneous effect of tidal state, wind speed, temperature, habitat preference, and species abundance of one species on the other by means of multiway contingency tables and loglinear models. Diets of both species were similar and reflected the natural abundances of prey items in the tidal flats. Both species were strongly influenced by tidal state when selecting foraging habitat, but other factors modified their preferences. I found that the foraging behavior of American Oystercatchers was determined solely by abiotic factors; i.e., tidal state, foraging period, and a higher order interaction effect between wind speed and tidal state. By contrast, no combination of abiotic factors was sufficient to explain the observed abundances of Magellanic Oystercatchers. Instead, their foraging behavior was facilitated by the presence of congeners in addition to abiotic factors.

The Influence of Group Size On Predator Scanning and Foraging Behaviour of Wedgecapped Capuchin Monkeys (Cebus Olivaceus)

Behaviour ◽  
1986 ◽  
Vol 98 (1-4) ◽  
pp. 240-258 ◽  
Author(s):  
Jan R. De Ruiter
Keyword(s):  
Group Size ◽  
Foraging Behaviour ◽  
Group Formation ◽  
Food Competition ◽  
Food Sources ◽  
Capuchin Monkeys ◽  
Time Budgets ◽  
Large Group ◽  
Cebus Olivaceus ◽  
Travel Distances

AbstractThe behaviour of two groups of wedgecapped capuchin monkeys, Cebus olivaceus, a small one (n = 8) and a large one (n = 25) was recorded. Time budgets and other aspects of behaviour depended on group size. The differences can be explained as: adjustment to predation risk and intra-group food competition. In order to evade predation, members of the small groups scan more and stay at greater heights than those of the large group. Higher food competition within the large group was reflected in the composition of its diet, in longer travel distances, and higher levels of social behaviour. In particular during the dry season, the large group exploited unattractive and risky food sources. These results support ALEXANDER'S hypothesis on the causes of group formation.

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