Breeding Dispersal Distance Research Articles

Site Fidelity, Mate Fidelity, and Breeding Dispersal in American Kestrels

We assessed mate fidelity, nest-box fidelity, and breeding dispersal distances of American Kestrels (Falco sparverius) nesting in boxes in southwestern Idaho from 1990 through 2006. Seventy-seven percent of boxes had different males and 87% had different females where nest-box occupants were identified in consecutive years. High turnover rates were partly a result of box-switching. Forty-eight percent of males and 58% of females that nested within the study area in successive years used different boxes. The probability of changing boxes was unrelated to gender, nesting success in the prior year, or years of nesting experience. Breeding dispersal distances for birds that moved to different boxes averaged 2.2 km for males (max = 22 km) and 3.2 km for females (max = 32 km). Approximately 70% of birds that nested in consecutive years on the study area had a different mate in the second year. Mate fidelity was related to box fidelity but not to prior nesting success or years of nesting experience. Mate changes occurred 32% of the time when the previous mate was known to be alive and nesting in the area. Kestrels that switched mates and boxes did not improve or decrease their subsequent nesting success. Kestrels usually switched to mates with less experience and lower lifetime productivity than their previous mates. The costs of switching boxes and mates were low, and there were no obvious benefits to fidelity. The cost of “waiting” for a previous mate that might have died could be high in species with high annual mortality.

The effects of sex, age and breeding success on breeding dispersal of pied flycatchers along a pollution gradient

We modelled breeding dispersal of an insectivorous bird, the pied flycatcher (Ficedula hypoleuca) around a point source of heavy metals (a copper smelter). We tested for the effects of sex, age, breeding success and environmental pollution on breeding dispersal distances of F. hypoleuca females and males. Unlike many earlier studies on breeding dispersal, we took into account distance-dependent sampling bias by including in our model the recapture probabilities at different distances from the site of origin. Our results show that F. hypoleuca females disperse much farther (on average 7.9 km) from their breeding sites than what was previously thought. In contrast, males only disperse short distances (on average 190 m). Breeding success affected female breeding dispersal distances depending on female age: young females moved on average 8 km from their previous breeding place irrespective of their breeding success, while old females only seemed to move this far when their fledgling production was good. Females successful in their breeding dispersed as far as less successful females, or, among old birds, even farther. Females which dispersed long distances produced more fledglings after the movement than those staying near their previous breeding site. Degree of environmental pollution had no effect on female or male breeding dispersal distances. A polluted and unproductive environment does not seem to stimulate F. hypoleuca parents to move to more profitable territories.

Breeding Dispersal In the California Spotted Owl

Abstract Spotted Owls (Strix occidentalis) are territorial, generally nonmigratory, and strongly philopatric. Nevertheless, California Spotted Owls (S. o. occidentalis) exhibited breeding dispersal during 7% of interannual observations of banded individuals (n = 54 of 743 occasions). Based on ecological theory and published literature, we made a priori predictions about the factors associated with the probability of breeding dispersal and breeding dispersal distance, and about the consequences of dispersal. Breeding dispersal probability was higher for younger owls, single owls, paired owls that lost their mates, owls at lower quality sites, and owls that failed to reproduce in the year preceding dispersal. Sex had little effect on the probability of breeding dispersal. Dispersal distance was similar for female and male owls (median = 7 km, range = 1–33 km). We found no strong relationships between dispersal distance and any of the conditions that were associated with the probability of breeding dispersal. Dispersal resulted in improved territory quality in 72% of cases. These results indicate that breeding dispersal was condition-dependent and adaptive.

Breeding Dispersal In the California Spotted Owl

Abstract Spotted Owls (Strix occidentalis) are territorial, generally nonmigratory, and strongly philopatric. Nevertheless, California Spotted Owls (S. o. occidentalis) exhibited breeding dispersal during 7% of interannual observations of banded individuals (n = 54 of 743 occasions). Based on ecological theory and published literature, we made a priori predictions about the factors associated with the probability of breeding dispersal and breeding dispersal distance, and about the consequences of dispersal. Breeding dispersal probability was higher for younger owls, single owls, paired owls that lost their mates, owls at lower quality sites, and owls that failed to reproduce in the year preceding dispersal. Sex had little effect on the probability of breeding dispersal. Dispersal distance was similar for female and male owls (median = 7 km, range = 1–33 km). We found no strong relationships between dispersal distance and any of the conditions that were associated with the probability of breeding dispersal...

Biased estimates of fitness consequences of brood size manipulation through correlated effects on natal dispersal

Summary Dispersal of parents and offspring in relation to manipulated brood size were analysed in the great tit Parus major (L.) to study the potential confusion between dispersal and survival. The study area consisted of eight woodlots interspersed with nonbreeding habitat. The maximum distance between nestboxes was 10 km. The brood size of pairs with similar clutch size and laying date was manipulated in 3 years when chicks were 2 days old (1995, 1997 and 1998). Three nestlings were removed from one and added to another brood while a third was kept as a control. Offspring were measured, weighed and marked and breeding birds were captured and marked to allow dispersal estimates. For the offspring, dispersal was estimated as the distance between the natal nestbox and the nestbox of first breeding (natal dispersal distance) and, for the parents, as the distance between breeding boxes in two subsequent seasons (breeding dispersal distance). Natal dispersal distance was positively affected by brood size manipulation. This effect was more pronounced in males than in females. Breeding dispersal distance was not affected by manipulation. The practical consequence of this finding is that fitness estimates used to measure selection on brood size did depend on the spatial scale of the study area. For the Lauwersmeer population measured selection pressure changed from positive to stabilizing when I restricted the spatial scale of recovery. Other brood size manipulation experiments may suffer from similar biases in their fitness estimates. The biological consequence of this finding is that, if clutch size has a heritable component, local adaptation of clutch size will depend on the spatial heterogeneity of the habitat.

Pair bond and breeding success in Blue TitsParus caeruleusand Great TitsParus major

Data from 939 nests of the Blue TitParus caeruleusand 1008 nests of the Great TitP. majorfrom nestboxes provided in superabundance in mixed forest study sites between 1976 and 2001 were analysed to examine the effects of mate retention on breeding success and the relationship between mate fidelity and site fidelity. Most birds retained their former partner (76% in Great Tits and 65% in Blue Tits). The probability of a pair divorcing was affected by male age in Great Tits, divorce being more likely in pairs with first‐year males. Great Tit pairs breeding together for a second season bred earlier, but had no higher breeding success than pairs breeding together for the first time. In Blue Tits laying date and start of incubation tended to be earlier in pairs breeding together for a second season, but hatching and fledging dates were not earlier than in other pairs. Great Tit pairs breeding together for two consecutive seasons bred earlier in the second season than in the first, but breeding success did not differ significantly between years. In both species, breeding performance did not differ between pairs that divorced after a season and pairs that stayed together. Thus breeding success did not determine whether a pair divorced or bred together again. Neither Blue Tits nor Great Tits improved their breeding performance through divorce. Blue Tit females even had fewer fledglings in the year after divorce than in the year before. Mate retention affected breeding site fidelity. Blue Tit females had greater breeding dispersal distances between consecutive years when re‐mating than when breeding again with the same mate. In Great Tits both males and females dispersed more when re‐mating than when retaining the former partner, suggesting that mate retention increased the chance of retaining the breeding site. In both species, breeding dispersal distances did not differ between pairs that divorced and pairs in which one mate disappeared. Because no major advantage of mate retention was evident, we suggest that mate retention evolved under different conditions than those found in study sites with high breeding densities and a superabundance of artificial nesting sites.

Longer breeding dispersal than natal dispersal in the ortolan bunting

Theoretical models dealing with dispersal patterns are currently limited by a lack of empirical data, and existing data may be biased because of small spatial scale of many previous studies. We studied the whole known population of a small passerine bird, the ortolan bunting (Emberiza hortulana), in Norway. Males conducted extraordinary long-distance breeding dispersal of up to 45 km during their first years of life but showed high territory fidelity when older. Males that failed to attract a female in their first singing territory were especially likely to disperse, and their movements regularly occurred within a breeding season or until the next year (such movements were also defined as breeding dispersal). Breeding dispersal distances of males (median ¼ 11.9 km) were more than four times as long as their natal dispersal distances (median ¼ 2.7 km). These data contradict a classical view of dispersal in birds, namely, that the longest dispersal movements occur before the first territory is established (natal dispersal) and subsequent movements (breeding dispersal) are shorter. Thus, breeding dispersal plays a larger role than does natal dispersal in gene flow and population connectivity in the ortolan bunting. We suggest that short natal dispersal and subsequent long breeding dispersal within the breeding season may be an optimal dispersal strategy in ortolan buntings owing to their patchy distribution in our study area, and we predict that this may also be the case for other species with patchy or fragmented distribution. Key words: breeding dispersal, Emberiza hortulana, natal dispersal, ortolan bunting, territory switching. [Behav Ecol]

Limited dispersal by Nazca boobiesSula granti

We documented natal and breeding dispersal at several spatial scales by Galápagos Nazca boobiesSula granti, a wide‐ranging pelagic seabird. We found exceptionally low degrees of both types of dispersal despite these birds’ vagility. Median natal dispersal distances were 26 m and 105 m for males and females, respectively. Median breeding dispersal distances for both sexes were 0 m. No natal or breeding dispersals occurred from our study site at Punta Cevallos, Isla Española to six other colonies in the Galápagos, but we did document four long‐distance natal dispersals from Punta Cevallos to islands near the South American coast. Recaptures and dead recoveries of ringed birds showed long distance non‐breeding movements to the Central American coast and elsewhere in the eastern Pacific, contrasting with the very limited dispersal to breeding sites.

Factors affecting breeding dispersal of European ducks on Engure Marsh, Latvia

SummaryWe used up to 35 years of capture–recapture data from nearly 3300 individual female ducks nesting on Engure Marsh, Latvia, and multistate modelling to test predictions about the influence of environmental, habitat and management factors on breeding dispersal probability within the marsh.Analyses based on observed dispersal distances of common pochards and tufted ducks provided no evidence that breeding success in yeartinfluenced dispersal distance betweentandt+ 1.Breeding dispersal distances (yearttot+ 1) of pochards and tufted ducks were associated with a delay in relative nest initiation dates in yeart+ 1. The delay was greater for pochards (c. 4 days) than for tufted ducks (c. 2 days) when females dispersed > 0·8 km.Northern shovelers and tufted ducks moved from a large island to small islands at low water levels and from small islands to the large island at high water levels before the construction of elevated small islands (1960–82). Following this habitat management (1983–94), breeding fidelity was extremely high and not influenced by water level in the marsh for either species.Because pochard nesting habitats in black‐headed gull colonies were saturated during the entire study period, nesting females moved into and out of colonies with similar probabilities. Local survival probabilities and incubation body masses were higher for both yearlings (SY) and adults (ASY) nesting within gull colonies, suggesting that these females were of better quality than females nesting outside of the colonies.Tufted ducks showed higher probabilities of moving from islands to emergent marshes when water levels were higher both before and after habitat management. However, rates of movement for a given water level were higher during the period before management than after.Both pochards and tufted ducks exhibited asymmetric movement with respect to proximity to water, with higher movement probabilities to near‐water nesting locations than away from these locations.Multistate capture–recapture models provided analyses that were useful in investigating sources of variation in breeding dispersal probabilities.

Experimental increase of predation risk induces breeding dispersal of Tengmalm's owl.

Nest predation and its avoidance are critical components of an individual's fitness and play an important role in life history evolution. Almost all studies on this topic have been observational, and thus have not been able to separate the effects of individual quality, habitat selection and predation risk of given nest sites from each other. More experimental studies on nest predation and breeding dispersal, therefore, are needed to avoid confusing interpretations of the results. In western Finland, pine marten (Martes martes) predation risk was experimentally simulated at the nests of Tengmalm's owls (Aegolius funereus) by using a caged American mink (Mustela vison) as a predator. Nests without exposure to a mink served as controls. In accordance with our predictions and earlier observational studies, males exposed to simulated predation risk increased nest-hole shift and breeding dispersal distances compared to control males. Nest-hole shift and long breeding dispersal distances probably decrease the risk of nest predation, because pine martens are known to revisit nest-holes they have found.

Causes and Consequences of Territory Change and Breeding Dispersal Distance in the Black Kite

Causes and Consequences of Territory Change and Breeding Dispersal Distance in the Black Kite

The Effects of Car Traffic on Breeding Bird Populations in Woodland. II. Breeding Dispersal of Male Willow Warblers (Phylloscopus trochilus) in Relation to the Proximity of a Highway

1. In this study the dispersal activity of male willow warblers Phylloscopus trochilus breeding next to a highway carrying heavy traffic was investigated. 2. Breeding dispersal distances of yearling males along the road were larger than at further distances and were in the same order of magnitude as natal dispersal distances (medians being 303 and 515 m, respectively). 3. A simulation of dispersal directions, adjusted for actual landscape features, indicated that breeding dispersal was actively directed away from the road. 4. There appeared to be a relation between dispersal and breeding performance for yearling males, unsuccessful males moving more frequently and further (median 294 m) than successful males (median 120 m)

Breeding Dispersal in Spanish Pied Flycatchers Ficedula hypoleuca

Breeding dispersal of Pied Flycatchers was analysed over a six year period. Dispersal distances between consecutive breeding seasons did not differ between the sexes, although female dispersal was probably underestimated. Females were increasingly site-tenacious to at least their third reproduction, while males dispersed short distances within familiar areas irrespective of their age. Most individuals responded to variation in territory quality: the quality of the chosen nestbox was higher during their second than their first breeding attempt. This improved nest site selection was not correlated with breeding dispersal distance in females. However, males dispersing short distances acquired nestboxes of higher quality than those dispersing long distances. Pairs which remated between breeding seasons dispersed very short distances, while neither divorce nor death of the previous mate influenced dispersal in either sex. Contrary to the trend in many similar studies, males (but not females) rearing large broods dispersed further the following year. It is argued that breeding costs may be responsible for this pattern. Our results support the hypothesis of Pirt and Gustafsson (1989) that choice of breeding site is based on prior experience.

Breeding Dispersal in the Collared Flycatcher (Ficedula albicollis): Possible Causes and Reproductive Consequences

SUMMARY (1) Correlates of breeding dispersal (between years) in the collared flycatcher were analysed using data from a population on the Swedish island of Gotland in the Baltic. (2) Females on average moved further than males. Only 8% of the males and 2% of the females reoccupied their previous nest box. Individual size or body condition were not related to breeding dispersal. (3) Among females both total failures and reduced number of fledged young were associated with long subsequent movements in yearlings, whereas dispersal of older individuals was not related to previous breeding success. The pattern of breeding dispersal was similar in males but the difference was not significant. (4) Males that remained unpaired throughout the breeding season moved further in the next year than did mated males. There were no differences in breeding dispersal patterns between polygynous and monogamous males, nor between monogamous and secondary females. (5) Occupation of previous nest boxes by breeding tits were significantly correlated with dispersal distances in 2-year-old males, but not in older males. Female breeding dispersal was not related to this factor. (6) Males breeding for the first time in their natal area subsequently moved shorter distances than males breeding in another area. Females showed no significant differences in dispersal with respect to their birth place. (7) Breeding dispersal distance was not correlated with age when breeding success, occupation of previous nest boxes by breeding tits and distance from natal area were controlled for. (8) The reproductive correlates of movements were different for different categories of individuals. There was a negative correlation between distance moved and subsequent fitness (measured as survival and number of recruits produced) among previously successful females, whereas the trend was the opposite among previously unsuccessful females. These relationships were most prominent among young females. There were no significant correlations of dispersal and subsequent reproductive performance in males. (9) The hypothesis is advanced that breeding dispersal distances (to some extent) reflect individual choices among available territories, in that individuals with little and/or bad local experience disperse more because they benefit from exploring more sites before

Dispersal of Tengmalm's Owl Aegolius funereus in Relation to Prey Availability and Nesting Success

Among Tengmalm's Owls ringed in Norway, natal and female breeding dispersal distances were longer if dispersal took place during a microtine prey population low than if dispersal occurred within a microtine peak. Of the recorded cases of female breeding dispersal, 13% could be termed nomadic (dispersal distance > 100 km). Female and overall natal dispersal distances were longer than female breeding dispersal distances. Natal dispersal distances tended to be longer in females than males. Adult females dispersed farther after nest predation than after successful nesting. Extra mortality in adult females due to nest predation may only be small, and will in itself not select for nomadism, as recently suggested.