Flock size, food dispersion, and the feeding behavior of crossbills

C. W. Benkman

doi:10.1007/bf00300351

The Influence of Food Density, Flock Size, and Disturbance on the Functional Response of Bewick’s Swans (Cygnus columbianus bewickii) in Wintering Habitats

Animals ◽

10.3390/ani9110946 ◽

2019 ◽

Vol 9 (11) ◽

pp. 946 ◽

Cited By ~ 4

Author(s):

Chao Yu ◽

Lizhi Zhou ◽

Nazia Mahtab ◽

Shaojun Fan ◽

Yunwei Song

Keyword(s):

Feeding Behavior ◽

Functional Response ◽

Habitat Management ◽

Feeding Rate ◽

Handling Time ◽

Foraging Strategies ◽

Food Density ◽

Flock Size ◽

Functional Responses ◽

Cygnus Columbianus

Perceiving how animals adjust their feeding rate under a variety of environmental conditions and understanding the tradeoffs in their foraging strategies are necessary for conservation. The Holling functional response, which describes the relationship of feeding rate and food density to searching rate and handling time, has been applied to a range of waterbirds, especially with regard to Type II functional responses that describe an increasing feeding rate with food density but at a decelerating rate as the curve approaches the asymptote. However, feeding behavior components (feeding rate, searching rate, and handling time) are influenced by factors besides prey density, such as vigilance and flock size. In this study, we aim to elucidate how Bewick’s swans (Cygnus columbianus bewickii) adopt flexible foraging strategies and vary their feeding behavior components in response to disturbance, flock size, and food density. We collected focal sampling data on the foraging behavior of swans that foraged rice grains, foxnut seeds, and tubers in paddy field, foxnut pond, and lake habitats, respectively, in Shengjin and Huangpi lakes during winter from 2016 to 2018. The observed feeding rate was not correlated with food density and displayed a positive relationship with searching rate but negative relationships with handling time, flock size, overall vigilance time, and disturbance time. Handling time was negatively correlated with food density and flock size, yet it increased with disturbance, overall vigilance time, and normal vigilance time. Searching rate was negatively correlated with food density, flock size, and disturbance time. Feeding rate was affected by the combined effects of handling time and searching rate, as well as food density and searching rate. The shape of the observed functional response could not be fitted to Holling’s disc equation. However, the disc equation of the predicted feeding rate of wintering swans was found to be driven by food density. This provides insight into how wintering waterbirds adopt appropriate foraging strategies in response to complicated environmental factors, which has implications for wildlife conservation and habitat management.

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The effects of flock size and human presence on vigilance and feeding behavior in the Eurasian Coot (Fulica atra L.) during breeding season

acta ethologica ◽

10.1007/s10211-010-0089-y ◽

2010 ◽

Vol 14 (1) ◽

pp. 51-56 ◽

Cited By ~ 3

Author(s):

Çınar Severcan ◽

Elif Yamaç

Keyword(s):

Feeding Behavior ◽

Breeding Season ◽

Flock Size ◽

Human Presence ◽

Fulica Atra

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The effects of habitat density and the spatial distribution of food on the social behaviour of captive wintering American Tree Sparrows

Canadian Journal of Zoology ◽

10.1139/z87-081 ◽

1987 ◽

Vol 65 (3) ◽

pp. 522-526 ◽

Cited By ~ 3

Author(s):

David R. C. Prescott

Keyword(s):

Social Behaviour ◽

Ground Cover ◽

High Density ◽

Food Distribution ◽

Low Density ◽

Flock Size ◽

Nearest Neighbour ◽

The Social ◽

Food Dispersion ◽

Different Levels

Two artificial habitats containing 15% (low density) and 40% (high density) coniferous ground cover, and three feeding patterns representing different levels of spatial food distribution were used to investigate the effects of factors influencing individual spacing on the behaviour of captive, wintering American Tree Sparrows (Spizella arborea). Specifically, three aspects of social behaviour were examined: the frequency of agonistic encounters, the percentage of interactions initiated by dominants, and nearest-neighbour distances. Temperature effects were also considered. Interaction rates were lowest when food was most dispersed, and at higher temperatures. More interactions were recorded in the higher density habitat, as compared with the low density habitat, but the trend was reversed when food was highly dispersed. Nearest-neighbour distances decreased with increasing habitat density and food dispersion and were shortest in the high density habitat. Dominant birds initiated most encounters (70.7%), but less frequently when food was abundant or temperatures high, contradicting an assumption of previous models of optimal flock behaviour. It is suggested that these models, which rely on predicted changes in the allocation of available time by dominant birds to predict flock size, could be improved by considering the effects of habitat density and food dispersion, as well as differences in the social optimization strategies of different flocking species.

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