Nest-guarding Behavior Research Articles

Chthonic severance: dinosaur eggs of the Mesozoic, the significance of partially buried eggs and contact incubation precursors.

For most dinosaurs, clutches consisted of a single layer of spherical to sub-spherical, highly porous eggs that were probably fully buried. Both eggs and clutch form change drastically with pennaraptoran theropods, the clade that includes birds. Here, far less porous, more elongate eggs are arranged with additional complexity, and only partially buried. While partial egg burial seems to be effective for an extremely small group of modern birds, the behaviour's overall rarity complicates our understanding of Mesozoic analogies. Recent experimental examination of pennaraptoran nesting thermodynamics suggests that partial egg burial, combined with contact incubation, may be more efficacious than has been presumed. We propose that nest guarding behaviour by endothermic archosaurs may have led to an indirect form of contact incubation using metabolic energy to affect temperature change in a buried clutch through a barrier of sediment, which in turn may have selected for shallower clutch burial to increasingly benefit from adult-generated energy until partial egg exposure. Once partially exposed, continued selection pressure may have aided a transition to fully subaerial eggs. This hypothesis connects the presence of partially buried dinosaurian clutches with the transition from basal, crocodile-like nesting (buried clutches guarded by adults) to the dominant avian habit of contact incubating fully exposed eggs. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

Plasticity in social behaviour varies with reproductive status in an avian cooperative breeder.

Cooperatively breeding vertebrates are common in unpredictable environments where the costs and benefits of providing offspring care fluctuate temporally. To balance these fitness outcomes, individuals of cooperatively breeding species often exhibit behavioural plasticity according to environmental conditions. Although individual variation in cooperative behaviours is well-studied, less is known about variation in plasticity of social behaviour. Here, we examine the fitness benefits, plasticity and repeatability of nest guarding behaviour in cooperatively breeding superb starlings (Lamprotornis superbus). After demonstrating that the cumulative nest guarding performed at a nest by all breeders and helpers combined is a significant predictor of reproductive success, we model breeder and helper behavioural reaction norms to test the hypothesis that individuals invest more in guarding in favourable seasons with high rainfall. Variation in nest guarding behaviour across seasons differed for individuals of different reproductive status: breeders showed plastic nest guarding behaviour in response to rainfall, whereas helpers did not. Similarly, we found that individual breeders show repeatability and consistency in their nest guarding behaviour while individual helpers did not. Thus, individuals with the potential to gain direct fitness benefits exhibit greater plasticity and individual-level repeatability in cooperative behaviour.

Spawning season and nest guarding behavior of invasive smallmouth bass (Micropterus dolomieu) in a Japanese Lake

AbstractSpawning of invasive smallmouth bass (Micropterus dolomieu) was studied in 2020 and 2021, in Lake Nojiri, Nagano, Japan. Male smallmouth bass began nest construction once water temperatures reached 14°C, and eggs progressed to fry dispersal in approximately 2 weeks. The main spawning season was in late May through early June, with a smaller second peak of nests in late June through early July. Nests were constructed primarily under dock cover, and nest size and depth were positively correlated with male body size. Of the nests that received eggs, nearly all progressed successfully to fry dispersal. Time lapse videos of male guarding behavior revealed that as nests progressed, males rotated less and were suspended off the bottom substrate. Similarly, the presence of egg predators was determined by experimental removal of guarding males. Freshwater gobies (Rhinogobius kurodai) were the only egg predators observed and arrived on all nests in the egg stage. However, only a handful of gobies visited each nest, the total number of eggs predated was low, and eggs or alevins in the progressed stage were rarely predated. These results indicate that in Lake Nojiri, smallmouth bass spawning is highly successful and egg predators appear to have minimal effect on egg survival. The stable smallmouth bass fishery without stocking at this lake is likely a product of these favorable spawning conditions. The lack of native egg predators may also be a driving factor in the continued spread of smallmouth bass throughout Japan.

Nest guarding behaviour of a temperate wrasse differs between sites off Mediterranean CO2 seeps

Organisms may respond to changing environmental conditions by adjusting their behaviour (i.e., behavioural plasticity). Ocean acidification (OA), resulting from anthropogenic emissions of carbon dioxide (CO2), is predicted to impair sensory function and behaviour of fish. However, reproductive behaviours, and parental care in particular, and their role in mediating responses to OA are presently overlooked. Here, we assessed whether the nesting male ocellated wrasse Symphodus ocellatus from sites with different CO2 concentrations showed different behaviours during their breeding season. We also investigated potential re-allocation of the time-budget towards different behavioural activities between sites. We measured the time period that the nesting male spent carrying out parental care, mating and exploring activities, as well as changes in the time allocation between sites at ambient (~400 μatm) and high CO2 concentrations (~1000 μatm). Whilst the behavioural connectance (i.e., the number of linkages among different behaviours relative to the total amount of linkages) was unaffected, we observed a significant reduction in the time spent on parental care behaviour, and a significant decrease in the guarding activity of fish at the high CO2 sites, with a proportional re-allocation of the time budget in favour of courting and wandering around, which however did not change between sites. This study shows behavioural differences in wild fish living off volcanic CO2 seeps that could be linked to different OA levels, suggesting that behavioural plasticity may potentially act as a mechanism for buffering the effects of ongoing environmental change. A reallocation of the time budget between key behaviours may play a fundamental role in determining which marine organisms are thriving under projected OA.

Shelter Guarding Behavior of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) in North Carolina Streams

Cryptobranchus alleganiensis alleganiensis (Eastern Hellbender) is a fully aquatic salamander of conservation concern across the southeastern US. Characterization of shelter guarding by males and interspecific behavior during the breeding season in wild populations within the Blue Ridge ecoregion of North Carolina is lacking. To this end, we characterized diurnal video sequences of natural shelter-rock and nest-guarding behavior by male Eastern Hellbenders. We documented several intraspecific behaviors between resident males and nonresident conspecifics (males and females) during the breeding season (late summer to early fall) of 2018–2019 using modified action cameras with 4–6 hour battery life deployed in the French Broad River Basin of western North Carolina. Breeding behavior was documented (gravid females entering shelter) in 5 shelters, with 4 nests later confirmed by researchers. Across 21 unique shelters, we documented several examples of aggressive behaviors by resident Eastern Hellbender males toward conspecifics, including defensive posturing, territorial behavior, fights, biting, and bite-holds. All males occupying shelters (residents) spent the majority of time actively guarding the shelter entrance (81.7% of video) followed by maintenance behavior (e.g., modifying the shelter entrance; 5.3% of video), and short bouts (mean = 3.2 minutes) away from the shelter rock (2.5% of video). This study provides the first quantitative report of male breeding-season behavior across multiple natural shelters using non-invasive, affordable, waterproof cameras in North Carolina. We report on the utility of this method for observing behavior in stream systems and its potential application for monitoring of nests and behavior in other diurnal aquatic species.

Potential Role of Strigeid Parasite Infection in the Maintenance of Alternate Reproductive Morphotypes in Bluegill Sunfish (Lepomis macrochirus)

Bluegill sunfish (Lepomis macrochirus) have two male morphotypes, α- and β-males, each differing in appearance and mating strategy. Alpha-males use nest-building tactics, whereas β-males use sneaker or satellite tactics. Lepomis macrochirus are important members of the aquatic community, and are often involved in parasitic life cycles. Among the most common parasites infecting L. macrochirus are strigeids, which include white grub (Posthodiplostomum minimum), black grub (Uvulifer ambloplitis), and yellow grub (Clinostomum marginatum). Previous studies found a higher abundance of strigeid parasites in α-males, even though β-males spend increased time in the littoral zone. One hypothesis is that α-males recruit the parasites during the spawn because of their nest-guarding behavior, which potentially increases their interactions with snail intermediate hosts. To test this hypothesis, L. macrochirus were collected between February and July in consecutive years from 2015 to 2017 from 13 lakes and ponds in northwestern Virginia. The fish were necropsied and all of the endo- and ectoparasites infecting the fish were identified and enumerated. The results supported the hypothesis and showed that α-males had greater infections postspawn, whereas β-males and females had no increase in infection from pre- to postspawn. Additionally, α-males recruited strigeid parasites at a greater rate than β-males, which negatively affected their body condition. The body condition of both α-males and females were negatively affected by P. minimum and U. ambloplitis, but β-males were not affected by either parasite. This shows that the differences in mating strategies between male morphotypes may result in greater strigeid infection in α-males compared with β-males. This may affect the fitness and reproductive output of α-males and be a contributing factor to the maintenance of β-males in the ecologically stable system, despite decreased reproductive success.

Predation risk and breeding site value determine male behavior and indirectly affect survivorship of their offspring

Predation is one of the main drivers of behavioral adaptation in prey. In species with parental care, predation can affect survival of both adults and the offspring under their care. This effect can be further modulated by or combined with other factors that contribute to mating and reproductive success of adults, such as the quality of their breeding site. Using the nest guarding behavior of a treefrog with paternal egg attendance, Kurixalus eiffingeri, we quantify the effects of predation on the behavior of adult frogs and the survival of their offspring. We observed predator avoidance behavior of male frogs guarding empty breeding sites or breeding sites with eggs in response to the introduction of a predatory snake, Dinodon rufozonatum. We hypothesized that male nest guarding behavior would be negatively correlated with predation risk and positively correlated with their clutch sizes. Furthermore, we predicted that predator avoidance in male frog would negatively impact the survivorship of their offspring. We found that breeding site fidelity in male frogs was determined by perceived predation risk and breeding site value, with more males abandoning sites when exposed to high mortality risks (presence of a snake) and when the reproductive benefits (number of offspring) were low. In addition, we found that the willingness of males to return to their breeding sites was positively correlated with their clutch sizes. Abandoning breeding sites, however, can be costly to males, because abandoned eggs had a lower hatching rate. Our findings provide empirical evidence of how the costs and benefits of predation risk and breeding site value can determine the behavior of an amphibian with parental care. When faced with predation risks, the willingness of individuals to maintain their ownership over nest sites can have significant effects on their reproductive success. For species with parental care, nest defense can also be critical for offspring survival. Using an East Asian treefrog with male egg attendance, we hypothesized that males would maximize their reproductive output by increasing investment for nest sites with low predation risks and with more offspring. We found that males are more likely to invest in nest attendance when risks are low and benefits of offspring survival are high. Moreover, we found that the willingness of males to continue parental investment resulted in an increase in survivorship of their offspring. Our results show that perceived risks and benefits to the adults are important factors in determining offspring survival in an amphibian species with parental care.

Factors Influencing Nest Survival in Florida Bass

AbstractAngling nesting Florida Bass Micropterus salmoides floridanus may influence the survival of the brood and could negatively affect bass populations. Our objectives were to estimate daily nest survival for Florida Bass and to examine factors that influence nest survival to the swim‐up fry stage. Snorkelers examined a total of 259 nests in a small, mesotrophic lake in north‐central Florida from 2010 to 2012. We compared nest survival rates with accumulated degree‐days, largest temperature drop following nest discovery, nest score, presence of a guarding male bass, and size of the guarding male. The most important factor in determining nest survival was the presence of a male bass. However, guarding male fish were only observed on 66% of active nests despite multiple visits to each nest, indicating a lower tendency to remain with the brood than has been reported in other Micropterus species. Florida Bass have displayed lower nest guarding behaviors in other studies; a prolonged spawning season and the presence of top predators in southern bass populations may influence decreased nest fidelity and nest guarding behavior. Individual nesting attempts may be less important for successful Florida Bass recruitment.Received September 28, 2016; accepted February 28, 2017 Published online May 12, 2017

Queen personality type predicts nest-guarding behaviour, colony size and the subsequent collective aggressiveness of the colony

The founding individuals of a new group or lineage are uniquely poised to have long-lasting effects on their descendants. Here we explore how the behavioural traits of new foundresses influence their task allocation strategies and the downstream collective behaviour of their colonies. We collected individual paper wasp (Polistes metricus) queens from the wild and measured their boldness, aggressiveness, exploration, activity and time budgets in the laboratory. We then provided queens with food and nest materials and waited for their workers to eclose. We subsequently tested for links between queen behavioural traits (e.g. boldness, aggressiveness) and the collective aggressiveness of their colonies, as estimated by the number of workers that responded to and stung a model predator. We found that bolder queens (i.e. queens that were less likely to leave their nests after repeated exposure to an agonistic stimulus) spent more time nest guarding, reared more workers and produced groups that were less responsive to a model predator. Thus, there appears to be parent–offspring, or queen–worker, resemblance in the degree to which individuals remain on their nests in different social contexts (solitary queen versus queen + her worker group). To our knowledge this represents the first study to explicitly test for links between individual variation in foundress behaviour, worker production and intercolony collective behaviour; the results highlight the possibility that cross-contextual and transgenerational behavioural links could be a reasonably common and potentially important phenomenon in complex societies.

Nest Guarding in Chesapeake Bay Bald Eagles

Abstract As Bald Eagle (Haliaeetus leucocephalus) populations approach carrying capacity in the Chesapeake Bay, competition for breeding territories appears to be intensifying. Frequent territorial interactions may force breeders to adjust nest-guarding behavior. We examined nest-guarding behaviors at active Bald Eagle nests in the lower Chesapeake Bay during the nesting season (2012 and 2013). Guarding coverage was 13.7 ± 4.2% of total observation time during the pre-laying period, 6.8 ± 2.2% of observation time in the incubation period, and 26.3 ± 3.2% of observation time in the nestling period. Females were present in the nest area for 80.0 ± 2.7% of the nestling period. Although males were present only 51.2 ± 2.8% of the nestling period, male breeders guarded nests twice as often as females. Adults guarded most often from perches in adjacent trees and within 25 m of the nest. If increasing rates of conspecific interactions force males to allocate more time to nest guarding, a tradeoff may occur, with ...

Predicting reproductive success from hormone concentrations in the common tern (Sterna hirundo) while considering food abundance.

In birds, reproductive success is mainly a function of skill or environmental conditions, but it can also be linked to hormone concentrations due to their effect on behavior and individual decisions made during reproduction. For example, a high prolactin concentration is required to express parental behaviors such as incubation or guarding and feeding the young. Corticosterone level, on the other hand, is related to energy allocation or stress and foraging or provisioning effort. In this study, we measured individual baseline prolactin and corticosterone between 2006 and 2012 in breeding common terns (Sterna hirundo) using blood-sucking bugs. Reproductive parameters as well as prey abundance on a local and a wider scale were also determined during this period. Baseline prolactin and corticosterone varied significantly between years, as did breeding success. At the individual level, prolactin was positively and corticosterone was negatively linked to herring and sprat abundance. At the population level, we also found a negative link between corticosterone and prey abundance, probably reflecting overall foraging conditions. High prolactin during incubation was mainly predictive of increased hatching success, potentially by supporting more constant incubation and nest-guarding behavior. It was also positively linked to a lesser extent with fledging success, which could indicate a high feeding rate of young. Corticosterone concentration was positively related to high breeding success, which may be due to increased foraging activity and feeding of young. In general, our study shows that baseline prolactin and corticosterone levels during incubation can predict reproductive success, despite the presence of an interval between sampling and hatching or fledging of young.

Active and effective nest defence by males in a social apoid wasp

Altruism in the social Hymenoptera is generally considered to be a feature of females rather than males. A popular explanation for this is that in the solitary ancestors of today's social species, males provided little brood care. Males might therefore lack the preadaptations necessary to evolve altruism in social contexts. While anecdotal observations of male contributions to colony life have been reported, there are few reports of male participation in nest defence. In apoid wasps, there have been several reports of male nest-guarding behaviour in solitary species, potentially setting the evolutionary stage for similar behaviours in social lineages. Here, we present evidence of active and effective nest defence in males of the social apoid wasp Microstigmus nigrophthalmus. Males were observed chasing intruders away from the nest, and the presence of males had a significant effect on nest survival when females were removed. Males potentially obtained direct benefits through defence, so that defence may not represent male altruism. However, our results do show that males can perform acts that benefit their colony.

Interference from long-tailed finches constrains reproduction in the endangered Gouldian finch

1. Interspecific interference competition for nest-sites among cavity-nesting birds can have important effects on reproductive fitness and the distribution of competing species. 2. We observed interference at nest-sites in free-living populations of the endangered Gouldian finch (Erythrura gouldiae) and sympatric long-tailed finch (Poephila acuticauda), and also experimentally tested the relative strength and effect of interference at nest-sites in captive populations. 3. Levels of competitive interference at nest-sites in the wild were high for Gouldian, but not long-tailed finches, and interference frequency was inversely related to Gouldian finch reproductive success. High levels of interference conferred reduced fledging success but did not affect offspring condition. 4. Captive experiments corroborated the field data, also demonstrating fitness costs of interspecific competition, and that long-tailed finches dominated resources under standardized conditions. 5. Such asymmetrical competition dynamics are likely to constrain reproduction in Gouldian finch populations, potentially affecting recruitment and hindering the recovery of remaining populations of this endangered species.

Stress and parental care: Prolactin responses to acute stress throughout the breeding cycle in a long-lived bird

While the role of corticosterone in mediating the response of birds to acute stress is well established, it has recently been proposed that a decrease in prolactin levels following stress may complement corticosterone in redirecting resources away from breeding activities and towards behaviors promoting immediate survival. Here, for the first time, we detail changes in the prolactin stress response of birds throughout the breeding cycle. We then discuss the modulation of the corticosterone and prolactin stress responses over successive stages of breeding, differing in reproductive value and parental effort. In a long-lived Procellariiform seabird, the Manx shearwater Puffinus puffinus, we found that prolactin levels decreased in response to acute stress during incubation and mid chick-rearing but increased in response to stress during late chick-rearing and in non parenting birds, a pattern similar to that previously described for mammals. The high corticosterone stress response in pre-breeders was consistent with predictions based on reproductive value, but a similar response during late chick-rearing was not. This probably reflected foraging effort and a heightened importance of the parents’ own nutritional status at this stage of the season, in advance of post-breeding migration. We also found that baseline prolactin levels were maintained at high levels during chick-rearing and were only slightly lower during late chick-rearing and in failed breeders and non-breeders. These data suggest that prolactin may play a role in nestling care long beyond the brooding phase, that this is not due to birds spending long periods away from the colony and that prolactin secretion may be necessary for nest-guarding behavior.

Honeybee, Apis mellifera, guards use adaptive acceptance thresholds to limit worker reproductive parasitism

To protect their colonies from robbing by conspecifics, honeybees have evolved nest-guarding behaviour. Guards adjust their acceptance threshold so that, as the likelihood of robbing increases, fewer non-nestmates are admitted. In addition to the possibility of robbing, queenless colonies may be infiltrated by reproductively parasitic non-nestmates. We tested the hypothesis that queenless colonies would be more discriminatory of non-nestmates than queenright colonies. As predicted, queenless colonies accepted significantly fewer non-nestmates (from queenright colonies) than they did nestmates, whereas queenright colonies did not differentiate significantly between the two sources. This trend continued once laying workers became active in queenless colonies. Thus there is evidence that queenless colonies are more discerning against potential reproductive parasites than queenright colonies. We also tested the hypothesis that as the likelihood of an intruder being a reproductive parasite increased, guards would become less permissive of allowing it entrance to the colony. Queenright colonies accepted significantly more non-nestmates from queenright colonies (no active ovaries) than they did non-nestmates from queenless colonies (many with active ovaries). However, queenless colonies did not make this distinction. We suggest that to queenless colonies all non-nestmates are potential parasites.

Reproductive biology of Patagonotothen ramsayi (Regan, 1913) (Pisces: Nototheniidae) around the Falkland Islands

The reproductive biology of one of the most abundant notothenioids, Patagonotothen ramsayi, was investigated between February 2003 and November 2004 on the Falkland and Patagonian Shelves (Southwest Atlantic). Male and female P. ramsayi were mature at 27.6 and 24.8 cm L T, respectively. P. ramsayi is a total spawner, with a total fecundity ranging between 24,300 and 76,700 eggs. Spawning occurs on the shelf breaks between June and August with the peak in gonado-somatic indices in June. Analysis of length frequency distributions over the year and sex ratios of mature fish during the spawning season may indicate the presence of a nesting and nest guarding behaviour in male fish, similar to other rockcods. Features of its reproductive strategy, which enabled P. ramsayi to dominate the medium-sized demersal fishes on the Patagonian shelf are discussed and compared with those of other nototheniids and cottid sculpins from the Northern Hemisphere.

Territorial male gobies respond aggressively to sneakers but do not adjust their sperm expenditure

We investigated whether mating behavior (sperm expenditure, courtship rate, and nest guarding) varied according to different levels of sperm competition in territorial males of two goby species, the grass and the black gobies. We measured sperm expenditure (sperm released after 30 min from the beginning of the spawning), male courtship rate, and nest-guarding behavior in territorial males of both species during simulated spawnings, in which we varied the number of attending sneakers. Our results showed that, in both species, territorial males adjusted their effort in nest guarding to the presence of rival sneakers by increasing the time spent patrolling the territory and attacking the sneakers. In contrast, sperm expenditure and male courtship rate were not influenced by the number of attending sneakers. These results are in agreement with those reported for other fish with alternative mating tactics and help to interpret previous inconsistencies between theoretical predictions and measured levels of sperm released at different levels of sperm competition by sneakers of the two gobiids studied here. Key words: alternative male mating tactics, fish, sperm expenditure. [Behav Ecol]

Increased parental care cost for nest-guarding fish in a lake with hyperabundant nest predators

Although parental care increases offspring survival, providing care is costly, reducing parental growth and survival and, thereby, compromising future reproductive success. To determine if an exotic benthic predator might be affecting parental care by nest-guarding smallmouth bass (Micropterus dolomieu), we compared nest-guarding behavior and energy expenditures in two systems, one with a hyperabundant recently introduced predator, the round goby (Neogobious melanostomus). In Lake Erie, USA, smallmouth bass vigorously defended their nests from benthic round gobies. In Lake Opeongo, Canada, smallmouth bass were exposed to fewer and predominantly open-water predators and were less active in their nest defense. From scuba and video observations, we documented that nest-guarding smallmouth bass chased predators (99% of which were round gobies) nine times more frequently in Lake Erie than in Lake Opeongo. This heightened activity resulted in a significant decline in weight and energetic content of guarding males in Lake Erie but no change in Lake Opeongo males. Bioenergetic simulations revealed that parental care increased smallmouth bass standard metabolic rate by 210% in Lake Erie but only by 28% in Lake Opeongo. As energy reserves declined and offspring became increasingly independent, males in both lakes consumed more prey and spent more time foraging away from their nests; however, nest-guarding smallmouth bass consumed few prey and, in Lake Erie, rarely consumed round gobies. Therefore, increased parental care costs owing to the presence of round gobies could affect future growth, reproduction, and survival if smallmouth bass approach critically low energy reserves.

Behaviour and success of sneaker males in the sand goby, Pomatoschistus minutus

In this study we investigated in laboratory conditions the presence of alternative reproductive tactics in the sand goby and describe proximate factors affecting their expression and success. We describe the reciprocal interactions of resident males, females, and sneaking males. The pre-spawning phase proved to be important for successful nest intrusions by sneakers. The number of sneakers had no effect on the frequency of successful intrusions. When small males had exclusive access to nest sites, they built a nest and courted females, showing a full behavioural repertoire. The intensity of courtship was, however, strongly positively correlated with body size. Using microsatellite DNA markers we assessed paternity shares of territorial and sneaker males in a subset of all replicates. Following successful nest intrusion sneaker males fertilised 5–10% of the eggs. Our interpretation of the results is that sneaking in the sand goby is a conditional tactic, one that is less successful than the normal nest guarding behaviour, at least for one spawning event.

Sex roles, parental experience and reproductive success of eastern kingbirds,Tyrannus tyrannus

We quantified parental behaviour of eastern kingbirds during the incubation and nestling periods to determine parental roles, and to examine the impact of previous breeding experience (defined as having bred on the territory in the past) on behaviour and reproductive success. Females performed all incubation, while males spent more than 60% of their time in vigilant or nest guarding behaviour during incubation. Parental roles were not defined as sharply during the nestling period. Females spent more time vigilant, but males provisioned young at only 54% of the rate of females. Vigilance and nest watching were still primarily male duties. Male and female behaviour did not vary with the pair’s combination of experience (e.g. experienced–experienced versus inexperienced–inexperienced in previous–current breeding season, respectively) during either phase of reproduction, but experienced males were more vigilant during incubation and fed young relatively more than inexperienced males. Experienced females were also more efficient foragers. Although behaviour did not differ among the four combinations of pair experience, inexperienced pairs none the less lost the most young to starvation and predation. Consequently, inexperienced pairs fledged one less nestling per nesting attempt than did pairs with at least one experienced breeder. Our results suggest that having at least one experienced breeder substantially improved a pair’s reproductive success. We propose that female site fidelity is a safeguard to avoid the lower breeding success a female would incur if she were to move to a new territory and breed with an inexperienced male.