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At least 37 records · Page 2Linked to original sources
USGS1999

[Book review] Cowbirds and Other Brood Parasites by Catherine Ortega. Tucson, Arizona: University of Arizona Press (1998). The Avian Brood Parasites: Deception at the Nest by Paul A. Johnsgard. New York: Oxford University Press (1997) Parasitic Birds and their Hosts: Studies in Coevolution edited by S.I. Rothstein & S.K. Robinson. New York: Oxford University Press (1998)

We are in a golden age for the study of brood parasitism, judging from both the quantity and quality of recent scientific publications on cuckoos, cowbirds and parasitic finches by investigators working in Europe, the Americas, Africa and Asia. As Johnsgard (1997) remarks in his preface, the evolutionary, ecological, and behavioural questions posed by obligate brood parasites are among the most intriguing contemporary ornithological topics. Rothstein & Robinson (1998) explain that brood parasites make ideal subjects for testing the generality of models for the evolution of social and mating behaviour, foraging behaviour, spatial distribution, and vocal development, because the strategy of providing no parental care removes constraints imposed on other birds. Since Aristotle, people have been fascinated by brood parasites, but only in the past two decades has the number of investigators working on this topic reached a critical mass and created momentum that promises many breakthroughs. New studies are being completed so rapidly that a general book is inevitably out of date on some topics by the time it is published. A complete library on brood parasitism should add two recent volumes (Morrison et al. 1999; Smith et al., in press).to the three reviewed here.

Animal Behaviour↗
USGS2010

Sustained increase in food supplies reduces broodmate aggression in black-legged kittiwakes

The amount of food ingested by chicks has often been suggested as being the main proximate factor controlling broodmate aggression in facultatively siblicidal species. Although several experiments have demonstrated that short-term food deprivation causes a temporary increase in aggression, no study has, to our knowledge, experimentally manipulated overall food supplies and considered long-term effects on chick behaviour and life history traits. We provided supplemental food to breeding pairs of black-legged kittiwakes, Rissa tridactyla , over an entire breeding season and compared the aggressive behaviour of their chicks with that of chicks of control pairs. Control A-chicks (first to hatch) showed more frequent and intense aggression than their experimental counterparts. Furthermore, the more A-chicks begged and the lower their growth rate the more aggressive they were. The consequences of increased aggression for B-chicks (second to hatch) were lower begging rate, lower growth rate and lower survival. We thus provide evidence that a sustained increase in food availability affects broodmate aggression and chick survival at the nest and we discuss the various proximate and ultimate causes involved in the evolution of broodmate aggression.

Alaska↗
USGS1994

Phenotypic divergence of secondary sexual traits among sage grouse, Centrocercus urophasianus , populations

S age grouse, Centrocercus urophasianus , in an isolated montane basin near Gunnison, Colorado differ in several morphological and behavioural traits from conspecifics studied in other areas of the species' range. Both sexes in Gunnison are smaller than sage grouse elsewhere, and males possess differences in feather morphology as well. The mating behaviour of male sage grouse in three populations was examined to determine whether male strut displays of Gunnison sage grouse were behaviourally distinct. Behavioural analyses revealed Gunnison males perform strut displays at a slower rate than males in the two other sage grouse populations sampled. In addition, Gunnison males' strut displays contain unique visual and acoustical aspects. The most distinguishing attributes of Gunnison sage grouse were male secondary sexual characteristics including traits that correlate with mating success in other populations. Thus, phenotypic differences observed in the Gunnison population represent a divergence in expression of traits that are likely to be influenced by sexual selection. Recent models of speciation suggest that species characterized by intense sexual selection, such as those with lek mating systems, have the potential for rapid inter-populational divergence in male traits and female preferences leading to speciation.

Colorado↗
USGS2012

Predator evasion by white-tailed deer fawns

Despite their importance for understanding predator–prey interactions, factors that affect predator evasion behaviours of offspring of large ungulates are poorly understood. Our objective was to characterize the influence of selection and availability of escape cover and maternal presence on predator evasion by white-tailed deer, Odocoileus virginianus, fawns in the northern Great Plains, U.S.A. We observed 45 coyote, Canis latrans, chases of fawns, and we participated in 83 human chases of fawns during 2007–2009, of which, 19 and 42 chases, respectively, ended with capture of the fawn. Evasive techniques used by fawns were similar for human and coyote chases. Likelihood of a white-tailed deer fawn escaping capture, however, was influenced by deer group size and a number of antipredator behaviours, including aggressive defence by females, initial habitat and selection of escape cover, all of which were modified by the presence of parturient females. At the initiation of a chase, fawns in grasslands were more likely to escape, whereas fawns in forested cover, cultivated land or wheat were more likely to be captured by a coyote or human. Fawns fleeing to wetlands and grasslands also were less likely to be captured compared with those choosing forested cover, wheat and cultivated land. Increased probability of capture was associated with greater distance to wetland and grassland habitats and decreased distance to wheat. Use of wetland habitat as a successful antipredator strategy highlights the need for a greater understanding of the importance of habitat complexity in predator avoidance.

Animal Behaviour↗
USGS1998

Male traits, mating tactics and reproductive success in the buff-breasted sandpiper, Tryngites subruficollis

Buff-breasted sandpipers use a variety of mating tactics to acquire mates, including remaining at a single lek for most of the breeding season, attending multiple leks during the season, displaying solitarily or displaying both on leks and solitarily. We found that differences in body size, body condition, fluctuating asymmetry scores, wing coloration, territory location and behaviour (attraction, solicitation and agonistic) did not explain the observed variation in mating tactics used by males. Which males abandoned versus returned to leks was also not related to morphology or behaviour, and there was no tendency for males to join leks that were larger or smaller than the lek they abandoned. These results suggest that male desertion of leks was not dependent on a male's characteristics nor on the size of the lek he was presently attending. Males did join leks with larger males than their previous lek, perhaps to mate with females attracted to these larger 'hotshot' males. Males at both leks and solitary sites successfully mated. Lek tenure did not affect mating success, although lekking males appeared to mate more frequently than solitary males. Courtship disruption and to a lesser extent, female mimicry, were effective at preventing females from mating at leks, and may offer a partial explanation for female mating off leks. Our analysis that combined all males together within a year (regardless of mating tactic) indicated that males that attended leks for longer periods of time and that had fewer wing spots were significantly more likely to mate. Given some evidence that wing spotting declines with age, and that females inspect male underwings during courtship, the latter result suggests that female choice may play some role in determining male success. We suggest that male buff-breasted sandpipers may use alternative mating tactics more readily than males in other 'classic' lek-breeding species because: (1) unpredictable breeding conditions in this species' high arctic breeding range leads to low lek stability, which in turn hinders mate selection mechanisms mediated by male dominance and female choice; and (2) males are not constrained by morphological markings that indicate status or sex. Both characteristics may reduce the reproductive benefits associated with males adopting one mating tactic and result in a sort of scramble competition in which males switch between tactics as local conditions change.

Animal Behaviour↗
USGS1998

Certainty of paternity and paternal investment in eastern bluebirds and tree swallows

Extra-pair paternity is common in many socially monogamous passerine birds with biparental care. Thus, males often invest in offspring to which they are not related. Models of optimal parental investment predict that, under certain assumptions, males should lower their investment in response to reduced certainty of paternity. We attempted to reduce certainty of paternity experimentally in two species, the eastern bluebird, S ialia sialis , and the tree swallow, Tachycineta bicolor , by temporarily removing fertile females on two mornings during egg laying. In both species, experimental males usually attempted to copulate with the female immediately after her reappearance, suggesting that they experienced the absence of their mate as a threat to their paternity. Experimental males copulated at a significantly higher rate than control males. However, contrary to the prediction of the model, experimental males did not invest less than control males in their offspring. There was no difference between experimental and control nests in the proportion of male feeds, male and female feeding rates, nestling growth and nestling condition and size at age 14 days. We argue that females might have restored the males’ confidence in paternity after the experiment by soliciting or accepting copulations. Alternatively, males may not reduce their effort, because the fitness costs to their own offspring may outweigh the benefits for the males, at least in populations where females cannot fully compensate for reduced male investment.

Animal Behaviour↗
USGS1999

Forced copulation results in few extrapair fertilizations in Ross's and lesser snow geese

Extrapair paternity varies from 0 to over 70% of young among various populations of birds. Comparative studies have suggested that this variation is related to nesting density, breeding synchrony and the proportion of extrapair copulations. We used minisatellite DNA fingerprinting to examine levels of extrapair paternity in Ross's geese, Chen rossi, and lesser snow geese, C. caerulescens c. (hereafter snow geese) nesting in the largest known goose colony in the world. These geese have one of the highest known percentages of extrapair copulation (46-56% of all attempted copulations), and all of these appeared to be forced. Among all successful copulations, 33 and 38% were extrapair in Ross's and snow geese, respectively. Despite the high percentage of extrapair copulations, extrapair paternity was low in both Ross's and snow geese (2-5% of young). Extrapair paternity was not related to nest density in either species. However, in snow geese, extrapair paternity was more likely to occur in nests of females that nested asynchronously, either early or late in the season. This is one of a few reported examples of a negative relationship between extrapair paternity and breeding synchrony. Extrapair young also tended to come from eggs laid later in the clutch. Although forced extrapair copulations appear to be a relatively inefficient reproductive tactic for males, they may provide a reproductive advantage for some males.

Animal Behaviour↗
USGS2000

Mate fidelity and breeding site tenacity in a monogamous sandpiper, the black turnstone

We examined the relationship between mate fidelity and breeding site tenacity during a 5-year study of the black turnstone, Arenaria melanocephala, a socially monogamous sandpiper breeding in subarctic Alaska. We tested the predictions of several hypotheses regarding the incidence of divorce and the benefits of fidelity to mate and breeding site. Interannual return rates to the breeding grounds (88% for males, 79% for females) were among the highest yet recorded for any scolopacid sandpiper, and 88% of returning birds nested on their previous year's territory. The annual divorce rate was only 11%, and mate fidelity was significantly linked to fidelity to territory but independent of sex and year. Males arrived in spring significantly earlier than their mates and interannual fidelity was influenced by the relative timing of arrival of pair members. Reunited pairs had significantly higher fledging success than new pairs formed after death or divorce. The incidence of divorce was unrelated to reproductive success the previous year, although birds nested significantly further away after failure than after a successful nesting attempt. Sightings of marked individuals suggested that members of pairs do not winter together, and breeding site tenacity provides a mechanism through which pair members can reunite. We reject the 'incompatibility' hypothesis for divorce in turnstones, and our data contradict predictions of the 'better option' hypothesis. Alternatively, we propose the 'bet-hedging' hypothesis to explain the occurrence of divorce, which transpires when an individual pairs with a new mate to avoid the cost of waiting for a previous mate to return. Such costs can include remaining unmated, if the former mate has died, or experiencing lower reproductive success because of delayed breeding.

Animal Behaviour↗
USGS2002

Ontogenetic improvement of visual function in the medaka Oryzias latipes based on an optomotor testing system for larval and adult fish

We developed a system for evaluation of visual function in larval and adult fish. Both optomotor (swimming) and optokinetic (eye movement) responses were monitored and recorded using a system of rotating stripes. The system allowed manipulation of factors such as width of the stripes used, rotation speed of the striped drum, and light illuminance levels within both the scotopic and photopic ranges. Precise control of these factors allowed quantitative measurements of visual acuity and motion detection. Using this apparatus, we tested the hypothesis that significant posthatch ontogenetic improvements in visual function occur in the medaka Oryzias latipes , and also that this species shows significant in ovo neuronal development. Significant improvements in the acuity angle alpha (ability to discriminate detail) were observed from approximately 5 degrees at hatch to 1 degree in the oldest adult stages. In addition, we measured a significant improvement in flicker fusion thresholds (motion detection skills) between larval and adult life stages within both the scotopic and photopic ranges of light illuminance. Ranges of flicker fusion thresholds ( X ±SD) at log I=1.96 (photopic) varied from 37.2±1.6 cycles/s in young adults to 18.6±1.6 cycles/s in young larvae 10 days posthatch. At log I=−2.54 (scotopic), flicker fusion thresholds varied from 5.8±0.7 cycles/s in young adults to 1.7±0.4 cycles/s in young larvae 10 days posthatch. Light sensitivity increased approximately 2.9 log units from early hatched larval stages to adults. The demonstrated ontogenetic improvements in visual function probably enable the fish to explore new resources, thereby enlarging their fundamental niche.

Animal Behaviour↗
USGS1979

Scent-marking in lone wolves and newly formed pairs

Scent-marking was studied in wolves (Canis lupus) along 133 km of tracks in northern Minnesota during winters of 1975 to 1976 and 1976 to 1977 and in two captive packs and four captive pairs for various periods. Lone wolves, which possess neither mates nor territories, rarely marked by raised-leg urination and defaecated and urinated less along roads and trails, where territorial pairs and packs generally marked. Newly formed pairs marked the most, eventually decreasing their rates to those of established packs. Generally, wolves that scent-marked also bred, whereas non-marking wolves usually did not breed. Scent-marking apparently is important to the success of courtship in new pairs and to reproductive synchrony in established pairs, as well as serving a territorial function.

Animal Behaviour↗
USGS1992

Group foraging by a stream minnow: shoals or aggregations?

The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

Animal Behaviour↗
USGS1995

DNA fingerprint similarity between female and juvenile brown-headed cowbirds trapped together

This DNA fingerprinting study investigates whether females of the brood parasite brown-headed cowbird, Molothrus ater, associate with their own juvenile offspring at feeding sites more often than would be expected by chance. Cowbirds lay their eggs in the nests of a variety of host species and, as far as is known, leave them to the care of foster parents. Using baited walk-in funnel traps, 36 adult female-juvenile pairs (or trios) of cowbirds were trapped. Blood samples were collected from these individuals to conduct DNA fingerprinting analyses, calculate similarity indices, and to compare S-values for the 11 comparisons of juveniles and the females with which they were caught with S-values of random pairings of juveniles and the females in adjacent gel lanes with which they were not caught. Overall band-sharing was significantly higher for the individuals trapped together than for the random pairings. These associations between juvenile cowbirds and their mothers could occur as a result of female cowbirds monitoring the development of their young in the nests where they have laid. Alternatively, nestling cowbirds in the nest could become familiar visually and locally with a female parent that is frequently in their territory and could follow her when she departs for feeding grounds. In either case these data suggest that adult cowbirds associate with juveniles, in some cases their own offspring, and that offspring may learn to function as cowbirds in part from this association.

Animal Behaviour↗
USGS2005

Disentangling association patterns in fission-fusion societies using African buffalo as an example

A description of the social network of a population aids us in understanding dispersal, the spread of disease, and genetic structure in that population. Many animal populations can be classified as fission–fusion societies, whereby groups form and separate over time. Examples discussed in the literature include ungulates, primates and cetaceans (Lott and Minta, 1983, Whitehead et al., 1991, Henzi et al., 1997, Christal et al., 1998 and Chilvers and Corkeron, 2002). In this study, we use a heuristic simulation model to illustrate potential problems in applying traditional techniques of association analysis to fission–fusion societies and propose a new index of association: the fission decision index (FDI). We compare the conclusions resulting from traditional methods with those of the FDI using data from African buffalo, Syncerus caffer , in the Kruger National Park. The traditional approach suggested that the buffalo population was spatially and temporally structured into four different ‘herds’ with adult males only peripherally associated with mixed herds. Our FDI method indicated that association decisions of adult males appeared random, but those of other sex and age categories were nonrandom, particularly when we included the fission events associated with adult males. Furthermore, the amount of time that individuals spent together was only weakly correlated with their propensity to remain together during fission events. We conclude with a discussion of the applicability of the FDI to other studies.

Kruger National Park↗
USGS2006

Do migratory flight paths of raptors follow constant geographical or geomagnetic courses?

We tested whether routes of raptors migrating over areas with homogeneous topography follow constant geomagnetic courses more or less closely than constant geographical courses. We analysed the routes taken over land of 45 individual raptors tracked by satellite-based radiotelemetry: 25 peregrine falcons, Falco peregrinus, on autumn migration between North and South America, and seven honey buzzards, Pernis apivorus, and 13 ospreys, Pandion haliaetus, on autumn migration between Europe and Africa. Overall, migration directions showed a better agreement with constant geographical than constant geomagnetic courses. Tracks deviated significantly from constant geomagnetic courses, but were not significantly different from geographical courses. After we removed movements directed far from the mean direction, which may not be migratory movements, migration directions still showed a better agreement with constant geographical than constant geomagnetic courses, but the directions of honey buzzards and ospreys were not significantly different from constant geomagnetic courses either. That migration routes of raptors followed by satellite telemetry are in closer accordance with constant geographical compass courses than with constant geomagnetic compass courses may indicate that geographical (e.g. based on celestial cues) rather than magnetic compass mechanisms are of dominating importance for the birds' long-distance orientation.

Animal Behaviour↗
USGS2007

Sexual selection in the squirrel treefrog Hyla squirella: the role of multimodal cue assessment in female choice

Anuran amphibians have provided an excellent system for the study of animal communication and sexual selection. Studies of female mate choice in anurans, however, have focused almost exclusively on the role of auditory signals. In this study, we examined the effect of both auditory and visual cues on female choice in the squirrel treefrog. Our experiments used a two-choice protocol in which we varied male vocalization properties, visual cues, or both, to assess female preferences for the different cues. Females discriminated against high-frequency calls and expressed a strong preference for calls that contained more energy per unit time (faster call rate). Females expressed a preference for the visual stimulus of a model of a calling male when call properties at the two speakers were held the same. They also showed a significant attraction to a model possessing a relatively large lateral body stripe. These data indicate that visual cues do play a role in mate attraction in this nocturnal frog species. Furthermore, this study adds to a growing body of evidence that suggests that multimodal signals play an important role in sexual selection.

Animal Behaviour↗
USGS2008

Experimental evidence of vocal recognition in young and adult black-legged kittiwakes

Individual recognition is required in most social interactions, and its presence has been confirmed in many species. In birds, vocal cues appear to be a major component of recognition. Curiously, vocal recognition seems absent or limited in some highly social species such as the black-legged kittiwake , Rissa tridactyla . Using playback experiments, we found that kittiwake chicks recognized their parents vocally, this capacity being detectable as early as 20 days after hatching, the youngest age tested. Mates also recognized each other's long calls. Some birds reacted to their partner's voice when only a part of the long call was played back. Nevertheless, only about a third of the tested birds reacted to their mate's or parents' call and we were unable to detect recognition among neighbours. We discuss the low reactivity of kittiwakes in relation to their cliff-nesting habit and compare our results with evidence of vocal recognition in other larids.

Alaska↗