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1.

001-es BibID:BIBFORM022845
Első szerző:Barta Zoltán (biológus, zoológus)
Cím:The effects of predation risk on the use of social foraging tactics / Zoltán Barta, András Liker, Ferenc Mónus
Dátum:2004
Megjegyzések:The effects of predation on the use of social foraging tactics, such as producing and scrounging, are poorly known in animals. On the one hand, recent theoretical models predict increased use of scrounging with increasing predation risk, when scroungers seeking feeding opportunities also have a higher chance of detecting predators. On the other hand, there may be no relation between tactic use and predation when antipredator vigilance is not compatible with scanning flockmates. We investigated experimentally the effects of predation risk on social foraging tactic use in tree sparrows, Passer montanus. We manipulated predation risk in the field by changing the distance between shelter and a feeder. Birds visited the feeder in smaller flocks, spent less time on it and were somewhat more vigilant far from shelter than close to it. Increased predation risk strongly affected the social foraging tactic used: birds used the scrounger tactic 30% more often far from cover than close to it. Between-flock variability in scrounging frequency was not related to the average vigilance level of the flock members, and within-flock variability in the use of scrounging was negatively related to the vigilance of birds. Our results suggest that in tree sparrows, the increased frequency of scrounging during high predation risk cannot simply be explained by an additional advantage of increasing antipredator vigilance. We propose alternative mechanisms (e.g. increased stochasticity in food supply, and that riskier places are used by individuals with lower reserves) that may explain increased scrounging when animals forage under high predation risk
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Animal Behaviour. - 67 : 2 (2004), p. 301-308. -
További szerzők:Liker András Mónus Ferenc
Internet cím:DOI
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2.

001-es BibID:BIBFORM066150
Első szerző:Mónus Ferenc
Cím:Is foraging time limited during winter? : A feeding experiment with tree sparrows under different predation risk / Ferenc Mónus, Zoltán Barta
Dátum:2016
ISSN:0179-1613
Megjegyzések:Small passerines are faced with a trade-off when foraging during winter. Increasing energy reserves makes them more vulnerable to predators, while a low level of reserves exposes them to a high risk of starvation. Whether small birds under these circumstances are allowed to reduce their foraging activity under increased predation risk, for example in feeding sites more exposed to predators, remains controversial in former behavioural and ecological researches. In this study, we investigated the foraging activity of free-living Tree Sparrow Passer montanus flocks feeding on an artificial feeding platform. The predation risk perceived by the sparrows was manipulated by placing the platform either close to or far from a bushy shelter. Foraging activity, assessed as cumulative activity of sparrows per unit time on the platform, did not differ between the low-risk and the high-risk conditions and did not significantly change during the day. Feeding efficiency, assessed as pecking rate, was not either reduced under the high-risk condition. Our results suggest that sparrows were forced to feed almost continuously during the day in order to maintain their preferred level of energy reserves. However, several behavioural changes helped sparrows to adopt a safer foraging policy when feeding far from cover, as we found in another study. Altogether, sparrow flocks feeding far from cover decreased the overall foraging time (the time when any sparrow stayed on the platform) by approximately 20% as compared to the near cover condition. A possible way to maintain the same level of foraging activity despite of the reduction in overall foraging time is discussed.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
foraging activity
predation risk
time-limited foraging
Tree Sparrow
Megjelenés:Ethology 122 : 1 (2016), p. 20-29. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:T-46661
OTKA
K75696
OTKA
4.2.1./B-09/1/KONV-2010-0007
TÁMOP
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM030383
035-os BibID:(WoS)000297951000005 (Scopus)80053250376
Első szerző:Mónus Ferenc
Cím:Intersexual size and plumage differences in tree sparrows (Passer montanus) : a morphological study based on molecular sex determination / F. Mónus, K. Szabó, A. Lózsa, Z. Pénzes, Z. Barta
Dátum:2011
ISSN:1217-8837
Megjegyzések:We investigated intersexual morphological differences in tree sparrows (Passer montanus), a species being considered as sexually monomorphic. Molecular sexing of the birds was performed by PCR amplification of the sex chromosome-linked CHD1 gene introns. All measured traits (body weight, wing, tail and tarsus length, bill size and the size of the black throat patch, i.e. badge hereafter) were greater in males than in females and the sex of about 90% of the individuals was correctly categorized by means of a discriminant analysis based on the morphological measurements. Nevertheless, wing length alone was equally good predictor of the sex. Other measured traits had only moderate discriminant value. Our results do not support that tree sparrows can be sexed based on the size of their badge alone. However, some of our results suggest intersexual differences in the function of the badge.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény hazai lapban
folyóiratcikk
intersexual differences
morphology
sex determination
tree sparrow
Passer montanus
Megjelenés:Acta Zoologica Academiae Scientiarum Hungaricae. - 57 : 3 (2011), p. 269-276. -
További szerzők:Szabó Krisztián (1975-) (zoológus) Lózsa Anita Pénzes Zsolt Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
Szerző által megadott URL
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4.

001-es BibID:BIBFORM022838
035-os BibID:(WoS)000231480100006 (Scopus)33646754891
Első szerző:Mónus Ferenc
Cím:Repeatability analysis of egg shape in a wild tree sparrow (Passer montanus) population : a sensitive method for egg shape description / Mónus F., Barta Z.
Dátum:2005
ISSN:1217-8837
Megjegyzések:The shape of avian eggs varies widely among and within species. To explore this variation, several methods for egg shape description were used in previous works. The simplest methods were unsuitable to detect small differences in shape of different eggs, while more elaborated methods required special equipment, since they were not generally used. In this study we present a simple method for egg shape description which incorporate quickness in the field, high sensitivity to egg shape differences and furthermore require no special equipment. The method is based on a function which describe the outline of the egg in a two dimensions co-ordinate system and outline originates from field taken photographs. The method was tested on clutches of wild living Tree Sparrow (Passer montanus) population. Three out of four parameters of the function were found to be repeatable in Tree Sparrows. The eggs of repetitive clutches of females were more similar considering these egg shape parameters than eggs of different females. A simple, widely used index to describe egg shape, egg shape index was found to be far less sensitive in our repeatability analyses. The method described here may be particularly suitable to investigate intraspecific variation of egg shape.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
egg shape, description, repeatability, Tree Sparrow, Passer montanus
Megjelenés:Acta Zoologica Academiae Scientiarum Hungaricae. - 51 : 2 (2005), p. 151-162. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM019035
Első szerző:Mónus Ferenc
Cím:Degree of synchronization of tree sparrows in flocks under different predation risk / Ferenc Mónus, Zoltán Barta
Dátum:2011
ISSN:0005-7959
Megjegyzések:When exposed to predators animals often benefit from synchronized movements and behaviour. In this study, we investigated the level of synchronization at arrivals at and departures from a feeding platform in flock-feeding tree sparrows (Passer montanus) under two different conditions; near to a protective cover or far from it. Sparrow flocks spent 43% less time in a feeding bout, and waited 30% more between bouts, far from the cover than near to it. The relationship of vigilance and flock size was different between the two conditions; the proportion of time allocated to vigilance increased more with decreasing flock size when far from the cover than when near to it. These results suggest that sparrows perceived higher predation risk when fed farther away from the protective cover. Furthermore, we found that far from the cover arrivals of sparrows were 79% more synchronized than when close to the cover. Finally, we did not find significant difference between the two feeding conditions in the synchronization at the departure. Possibly, due to its escape function, departures may be as synchronized as possible, even when feeding near to the protective cover
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
synchronized behaviour
predation risk
foraging
tree sparrow
Megjelenés:Behaviour. - 148 : 5-6 (2011), p. 733-744. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:Szerző által megadott URL
DOI
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6.

001-es BibID:BIBFORM019039
Első szerző:Mónus Ferenc
Cím:Seasonality and sociality in tree sparrows passer montanus / Ferenc Mónus, Zoltán Barta
Dátum:2010
ISSN:1734-624X
Megjegyzések:Despite the fact that the tree sparrow is often the object of behavioural studies and is a well-investigated species, no specific investigations were performed on the seasonal and daily pattern of the changes in flock size. Several observations suggest clear seasonal and daily periodicity of social organisation, and in connection with these changes, a similar periodicity in flock sizes. In this paper we present the results of a three-year observational study on the flock sizes of a suburban tree sparrow population. Our investigation resulted in statistical evidence for seasonal and daily periodic changes in the social organisation of the species. In the breeding season and in the mornings tree sparrows form smaller flocks than outside the breeding season and in the afternoons. Our results are consistent with the previous, non-systematic observations
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:International Studies of Sparrows. - 34 (2010), p. 18-22. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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7.

001-es BibID:BIBFORM018800
Első szerző:Mónus Ferenc
Cím:The effect of within-flock spatial position on the use of social foraging tactics in free-living tree sparrows / Ferenc Mónus, Zoltán Barta
Dátum:2008
ISSN:0179-1613
Megjegyzések:The benefit of producer (searches for own food) or scrounger (exploits the others' food discoveries) foraging tactic in a group of socially feeding animals may depend on where the individual searches for food within the group. Scrounging may be more advantageous in the centre of the group, having more individuals around to join, while producing may be more beneficial at the edges, where more unexplored food patches may be found. This study shows within-flock position correlates with forag- ing tactic use of feeding birds in socially foraging tree sparrows, Passer montanus. Sparrows staying closer to the centre of the flock found their food patches more requently by joining (i.e. use more frequently the scrounging tactic) than those staying toward the edges. To our knowledge this is the first field study demonstrating the relationship between spatial position and foraging tactic use. We investigated this relationship under different perceived predation hazard, and found that under elevated risk of predation, central individuals may increase their use of joining more than individuals on the periphery of the flock. Moreover, we show that extremely specialized use of searching tactics may be very infrequent in tree sparrows. As both within-flock position and search tactic use can be altered very quickly and without leaving the flock, individuals may easily alter them in order to adjust their behaviour.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Ethology. - 114 : 3 (2008), p. 215-222. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:NF 61143
OTKA
T-46661
OTKA
Internet cím:DOI
Intézményi repozitóriumban (DEA) tárolt változat
Borító:
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