Foraging site displacement in common crane flocks

Bautista, Luis M.; Alonso, Juan Carlos; Alonso, Javier

doi:10.1006/anbe.1998.0882

Cited by 54 publications

(36 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, in common cranes (Grus grus), where individuals often exploit their flock mates' food discoveries, aggressors increase their vigilance behaviour before attacking a flock mate and hence probably monitor the feeding success of their neighbours. As a consequence, these birds usurp the food resources of those flock mates whose intake rate is higher than average, thereby achieving an immediate increase in their own feeding rate (Bautista et al 1998). Birds might use cues other than flock mates' behaviour, i.e.…”

Section: Discussionmentioning

confidence: 99%

The effect of energy reserves on social foraging: hungry sparrows scrounge more

Lendvai

Barta

Liker

et al. 2004

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

Animals often use alternative strategies when they compete for resources, but it is unclear in most cases what factors determine the actual tactic followed by individuals. Although recent models suggest that the internal state of animals may be particularly important in tactic choice, the effects of state variables on the use of alternative behavioural forms have rarely been demonstrated. In this study, using experimental wind exposure to increase overnight energy expenditure, we show that flock-feeding house sparrows (Passer domesticus) with lowered energy reserves increase their use of scrounging (exploiting others' food findings) during their first feed of the day. This result is in accordance with the prediction of a state-dependent model of use of social foraging tactics. We also show that scrounging provides less variable feeding rates and patch finding times than the alternative tactic. These latter results support the theoretical assumption that scrounging is a risk-averse tactic, i.e. it reduces the risk of immediate starvation. As the level of energy reserves predicts the use of social foraging tactics, we propose that selection should favour individuals that monitor the internal state of flock mates and use this information to adjust their own tactic choice.

show abstract

Section: Discussionmentioning

confidence: 99%

The effect of energy reserves on social foraging: hungry sparrows scrounge more

Lendvai

Barta

Liker

et al. 2004

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

show abstract

“…State-dependent responses to competitors have been observed in common cranes Grus grus L. feeding on cereal seeds (Bautista, Alonso & Alonso 1998). Cranes attacked others feeding at higher rates than average birds in the flock.…”

Section: Introductionmentioning

confidence: 99%

Modelling state‐dependent interference in common cranes

Stillman

Bautista

Alonso

et al. 2002

Journal of Animal Ecology

View full text Add to dashboard Cite

Summary 1.Interference is a key component of food competition, but is difficult to measure in natural animal populations. Using data from a long-term study, we show that interference between common cranes Grus grus L., feeding on patches of cereal seeds, reduces intake rates at high competitor densities, and that the strength of interference is unrelated to food abundance.2. An alternative to measuring interference directly is to predict its strength using behaviour-based models. We test an interference model, originally developed for shorebirds feeding on invertebrate prey, for cranes. We compare the predictions of a rate-maximizing model, in which animals steal food if this increases intake rate, and a state-dependent model, in which they only rate-maximize if their intake rate is below a target value, otherwise they minimize injury risk by not stealing food. State-dependent aggression occurs in cranes. 3. The state-dependent model predicts more accurately the relative aggression rates of cranes of different dominance. However, both models predict accurately the observed strength of interference, that the strength of interference is unrelated to food abundance, at least within the observed range of crane and seed densities, and that cranes of a higher dominance have a higher intake rate than those of lower dominance. 4. This paper shows how state-dependent behaviour can be incorporated into an interference model, and that the model can produce accurate predictions for a system quite different to that for which it was developed.

show abstract

“…We defined the gross intake rate as the dry weight ingested per min of observation, the instantaneous intake rate as the dry weight ingested per min spent feeding with the head down. When we could not locate our marked bird in the flock (17% of the patches, Alonso et al 1995) we used the flock's average intake, after testing that the means of the differences between the marked bird and the flock members were not different from zero , Bautista et al 1998). For each day we calculated the accumulated food ingested in previous patches to study the trajectory of food intake with time of day.…”

Section: Behavior Of Marked Individualsmentioning

confidence: 99%

“…We scored the dominance of each crane by the percentage of successes in the aggressive interactions in which it was involved. First-year birds already independent from their parents were the least dominant birds and received most aggression from their flock mates (Bautista et al , 1998. Polo and Bautista (2006a, b) successfully applied a dobex model to body-mass gain of small birds, which show the typical diurnal foraging pattern with peaks in food consumption just after dawn and just before dusk.…”

Section: Behavior Of Marked Individualsmentioning

confidence: 99%

See 1 more Smart Citation

Factors Influencing Daily Food-Intake Patterns in Birds

Bautista¹,

Alonso²

2013

The Condor

Self Cite

View full text Add to dashboard Cite

Abstract. Avian foraging activity during daytime peaks after dawn and before dusk. The relative importance of each period of intensive foraging on the accumulated intake varies by species, individual, and day. We studied the relative importance of each period from direct observation of radio-tagged Common Cranes (Grus grus) during winter at a site of stopover and wintering in Spain. After a mathematical model was fitted, accumulated intake showed a typical anti-sigmoid shape, with greatest increases of intake after dawn and before dusk. The rise of accumulated intake decelerated until 50% of the day length, when the trajectory inflected and accelerated according to the fitted model. The trajectory of accumulated intake in territorial families that foraged in small home ranges with food predictably available but the cost of vigilance high decelerated until 20% of the day length, then accelerated for the rest of the day. In flocking nonterritorial cranes the inflection point was delayed until 60% of the day length, as expected since flocking cranes foraged in larger home ranges with food less predictable and the cost of vigilance lower. The inflection point was delayed in early winter and advanced in late winter. The changes in the inflection points of the functions for accumulated food intake may be straightforwardly applied to daily foraging routines of other species whose rates of intake may be recorded.

show abstract

Foraging site displacement in common crane flocks

Cited by 54 publications

References 39 publications

The effect of energy reserves on social foraging: hungry sparrows scrounge more

The effect of energy reserves on social foraging: hungry sparrows scrounge more

Modelling state‐dependent interference in common cranes

Factors Influencing Daily Food-Intake Patterns in Birds

Contact Info

Product

Resources

About