Nest-site Fidelity Research Articles

Evidence for Nest-Site Fidelity but Not Natal Homing in Bog Turtles (Glyptemys muhlenbergii)

To mitigate habitat loss and increase the reproductive success of threatened Bog Turtles (Glyptemys muhlenbergii), managers often improve or restore open-canopy nesting habitats within or adjacent to occupied habitat. Restoring nesting habitat, however, does not guarantee that Bog Turtles will use these restored habitats; inertial mechanisms such as nest-site fidelity and natal homing may prevent female Bog Turtles from discovering and using restored habitats for many years or even generations. The objective of this study was to improve understanding of the role behavioral inertia may play in female Bog Turtle nest-site selection. From 2008 to 2012, at nine fens in New York and Massachusetts, we compared the average distance between previous and subsequent nests with null distributions assuming no nest-site fidelity. We also assessed whether pairwise genetic relatedness of nesting females was positively associated with geographic distance between nests. We found evidence for strong but incomplete fidelity to nesting-habitat patches within a wetland, likely driven by behavioral inertia. Individuals nesting closer together were not more closely related, and first-degree female relatives did not consistently nest within the same nesting-habitat patch, suggesting that Bog Turtles do not exhibit natal homing. Our results suggest that Bog Turtle populations may be slow to respond to newly restored nesting areas because of behavior inertia. However, testing this hypothesis will require long-term monitoring of habitat-restoration efforts coupled with further investigations of Bog Turtle nest-site selection.

Black Tern Nest-site Fidelity in an Unstable Habitat: a Preliminary Study

We investigated the adult Black Tern (Chlidonias niger) return rate and nest-site fidelity in unstable habitats in the Kaniv reservoir (Middle Dnieper, Ukraine) where a regular weather impact such as heavy rains and storms leads to a destruction of nesting colonies. 278 adult birds were tagged with colored rings in 12 Black Tern colonies during the nesting season in 2012-2019. 44 Black Tern birds were resighted or recaptured in eight colonies. The return rate was 15.8 % and it declined rapidly in 3 years. 29 returning terns were noted within the same colonies where the birds had been tagged initially, 15 ones were seen in other colonies, but the majority of them were found no farther than 2 km from the initial colony. The site fidelity mean rate was 66 %. Olgin colony showed a high nest-site fidelity rate, while it was much lower in others. Such variations occurred because of the loss of first clutches caused by unfavorable weather conditions. In the middle of May, strong waves, storms and heavy rains regularly destroyed nesting colonies located in habitats poorly protected by water plant vegetation. Terns relocated their colonies to build new nesting clutches but commonly not farther then 2 km from their first colonies.

Nesting of Roseate Terns (Sterna dougallii) in Bermuda after Extirpation for Nearly 150 Years

In Bermuda, only three species of breeding seabirds survived four centuries of human activity, dating back to the settlement of the archipelago in 1609. This paper reports two consecutive years of nesting data on the Roseate Tern (Sterna dougallii), a historic breeder in Bermuda last recorded breeding in 1849. A pair was discovered incubating an egg on 7 July 2018 on Pearl Island, and a pair, plus one additional adult, returned to this islet to breed in 2019. Roseate Terns and nests were intensively monitored using offshore observations and video recordings. In 2018, the single egg hatched on 24 July and the chick fledged on 18 August (fledging period = 25 d). In 2019, we found a two-egg clutch on 4 June, which hatched on 15 and 17 June. The two chicks were flying by 13 July (fledging periods = 26-28 d). The breeding Roseate Terns in Bermuda are probably derived from the Caribbean/Bahamas population. The two-year nest-site fidelity of Roseate Terns, following absence for at least 140 years, suggests that this species is potentially reestablishing itself as a breeder in Bermuda. Future studies should determine the genetic origin of the birds, determine if the observed pairs are the same individuals using leg bands, record population growth, and compare the nesting biology of Bermudian Roseate Terns to that of the Bermudian Common Terns (Sterna hirundo).

Forced nest site relocations negatively affect reproductive investment in a colonial seabird species

Species breeding in urban environments are highly prone to a wide variety of non-natural, human activities, which range from short-term disturbances to the degradation or loss of suitable habitat. The latter in turn may force individuals to relocate to new sites for foraging or breeding, both of which presumably entails fitness costs due the trade-offs of finding and exploring new habitats. Species showing a high level of spatial foraging specialisation or nest site fidelity are expected to be most vulnerable. In this study, we explored the consequences of nest site loss on the reproductive investment of lesser black-backed gulls (Larus fuscus), a site faithful seabird species breeding in an urban environment. We monitored a population of 1.173 colour-ringed gulls across 13 years, that involved several episodes of spatially restricted loss of breeding habitat. We found that birds which lost their breeding territories reduced their investment into the eggs as reflected in a decrease of the clutch volume. They relocated over larger distances compared to birds that relocated voluntarily. Moreover, the likelihood of skipping the subsequent breeding season increased after a forced relocation. These negative effects of forced relocation likely contribute to the decline in the number of breeding pairs in our urban population as observed during the last ten years, and highlights the importance of maintaining a stable breeding environment in urban areas for the conservation of this and potentially other colonial breeding seabird species.

Breeding success, nest site fidelity and mate fidelity in the European Storm-petrel

The European Storm-petrel Hydrobates pelagicus is a monogamous and long-lived species with a low reproductive rate. Its nest sites are located in natural cavities under rocks or in burrows excavated by other species. Data obtained in the Molène archipelago, western France, have been analysed to study nest site fidelity and mate fidelity, and to study their relationship with breeding success and sex. Breeders were ringed and breeding success assessed from 2001–18. The influence of age and the weight of breeders on reproductive success has also been studied. Individuals were very faithful to their nest sites (94%) and to their mates (95%) from one year to the next. Breeding failure in the year t was negatively correlated with nest site fidelity and with mate retention in year t+1. Nest site fidelity was not influenced by the sex of breeding birds. Change of nest site or mate had no significant impact on the breeding success in the same year. There was a positive effect of the weight of incubating adults on reproductive success. High rates of nest site fidelity and mate fidelity may indicate good population status, with breeding habitat and mates of good quality.

Update of the population size and breeding performance of gentoo penguins (Pygoscelis papua) at Stranger Point/Cabo Funes, South Shetland Islands

The plasticity in the trophic ecology, the breeding phenology, and the low nesting site fidelity would be the reasons why most of the gentoo penguin (Pygoscelis papua) populations breeding in the western Antarctic Peninsula and islands of Scotia Arc remained stable or increasing, despite the changing environmental conditions. Regardless of the overall trend, recent studies revealed a decline in the abundance of some gentoo penguin populations at those regions. Therefore, it is highly valuable to update the population size of each colony in order to confirm the current trends of individual colonies and generate a comprehensive overview of the population status. We report the abundance and breeding performance of gentoo penguins at the Stranger Point/Cabo Funes colony from 2000/2001 to 2018/2019. During the last season, 5383 breeding pairs and 5545 chicks in creche were counted. Despite there were considerable inter-annual fluctuations over the study period, the total number of gentoo penguin breeding pairs increased by 74.6% (+ 3.1% per annum), while the number of chicks creched increased by 60.0% (+ 2.6% per annum). However, the index of breeding success remained relatively constant over time, varying between 0.74 and 1.23 chicks in creche/breeding pairs. Gentoo penguins have life-history strategies that are advantageous to face the environmental variability, allowing the species to maintain their breeding performance stable over time and enhance their resilience, which can favour the population growth at Stranger Point.

Nest-site fidelity and breeding dispersal by Common Tailorbirds in a tropical forest

BackgroundInformation pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.MethodsBy using mist nets and tracking the color banded individuals, we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds (Orthotomus sutorius) throughout a year and between successive years in 2017–2018.ResultsThe present study showed that Common Tailorbirds could produce up to four clutches per breeding season. When multiple broods were produced within a year, breeding pairs remained together, and the nest rebuilding rate was up to 92.2%, with only four cases (7.8%) in which birds reused their old nests. The dispersal distance between the nests during multiple breeding was found to be 10.0 ± 10.5 m, and nest-site fidelity within the same year was 90.0%. By the second year of breeding, 76.2% of individuals remained in the original breeding pairs, while for those that did switch partners, the females remained in the nest from the previous year and paired with new males. The dispersal distance between years was 26.5 ± 41.9 m, and nest-site fidelity between different years was 80.1%. There was no significant difference between within-year and between-year dispersal distances. Moreover, there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not.ConclusionsOur findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nest-sites, and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.

Nest-site fidelity in Lesser Kestrels: a case of Win–Stay/Lose–Shift?

We studied Lesser Kestrels’ (Falco naumanni) conditional nest-site fidelity, i.e., fidelity that depends on the outcome of the previous nesting attempt in that site. In particular, we were interested in examining whether individual kestrels practice a Win–Stay/Lose–Shift (WSLS) strategy towards their nest-sites; that is, does the tendency to use the same nest-site increase following a successful nesting season, but decrease following a failure. For that purpose, we documented the use of nest-sites by Lesser Kestrels and the breeding success in these sites during 1998–2003 in the city of Jerusalem (Israel). We found that while Lesser Kestrels do not practice WSLS strategy towards their nest-site, the males (but not the females) do so towards their sub-colony – they tend to stay in the same sub-colony if their nesting was successful, whereas they tend to migrate to a different sub-colony after failure. A possible explanation to this sexual difference in WSLS behavior can arise from the fact that changing a sub-colony entails a change of hunting area. The male, being the main food provider in the Lesser Kestrel, may be more sensitive to this opportunity.

Kin grouping is insufficient to explain the inclusive fitness gains of conspecific brood parasitism in the common eider.

Conspecific brood parasitism allows females to exploit other females' nests and enhance their reproductive output. Here, we test a recent theoretical model of how host females gain inclusive fitness from brood parasitism. High levels of relatedness between host and parasitizer can be maintained either by: (a) kin recognizing and parasitizing each other as a form of cooperative breeding or (b) natal philopatry and nest site fidelity facilitating the formation of kin groups, thereby increasing the probability of parasitism between relatives nesting in close proximity. To address these two hypotheses we genotyped feathers and hatch membranes of common eiders (Somateria mollissima) from western Hudson Bay, Canada, using a noninvasive sampling methodology. We found that most instances of brood parasitism do result in inclusive fitness gains. Furthermore, females with failed nests moved an average of 492m from their previous year's nest site, while successful females only moved an average of 13m. Therefore, we observed host-parasite relatedness can occur at levels higher than would be expected by chance even in the absence of kin grouping, suggesting that closely related females nesting near one another is not essential to maintain high host-parasitizer relatedness. In addition, kin grouping is only a transient phenomenon that cannot occur every year due to the propensity for females of failed nests to nest farther away from their nest site in subsequent years than females with successful nests, which provides support for kin recognition as a more likely mechanism to maintain high host-parasitizer relatedness over time.

Nesting ecology of flatback sea turtles Natator depressus from Delambre Island, Western Australia

Nest site selection is likely to be important for the fitness of sea turtle populations, but data on the environmental drivers of nest site selection and other important parameters like nest site fidelity and inter-nesting and remigration intervals are limited. We address these questions using data on flipper tag resightings and track counts from flatback turtles (Natator depressus) from Delambre Island in Western Australia collected over 2–3 weeks each nesting season across six nesting seasons. The median inter-nesting interval was 13 days (range 9–17 days) and the mean±s.d. remigration interval was 1.99±0.95 years. Turtles had around 10% probability of returning to the same sector of the beach (150-m-long sections). The median distance between subsequent emergences (whether false crawls were included or not) was ~450m. The number of turtles both emerging and successfully nesting was higher when air temperature and humidity were lowest and emergences increased slightly with tide height. Sector of the beach was by far the strongest predictor of nest site, with turtles showing preference for the less exposed side of the island. The results of this study will assist with future monitoring of this population and the management of threats related to coastal development and activities.

When the "selfish herd" becomes the "frozen herd": spatial dynamics and population persistence in a colonial seabird.

Aggregations are common in ecological systems at a range of scales and may be driven by exogenous constraints such as environmental heterogeneity and resource availability or by "self-organizing" interactions among individuals. One mechanism leading to self-organized animal aggregations is captured by Hamilton's "selfish herd" hypothesis, which suggests that aggregations may be driven by an individual's effort to minimize their risk of predation by surrounding themselves with conspecifics. We demonstrate that aggregations observed in Adélie Penguin (Pygoscelis adeliae) colonies are a convolution of both self-organized dynamics and external forcing arising from landscape terrain. In fluid, highly mobile aggregations, individuals are constantly moving in response to changing environmental conditions, the locations of predators, or the movements of conspecifics. However, when the ability to rearrange is limited and spatial reconfiguration occurs on slower time scales than changes in population size, systems may become trapped in suboptimal arrangements. We use simulated annealing to demonstrate that Adélie Penguin colonies are frozen in suboptimal spatial arrangements, and employ an individual-based modeling approach to demonstrate that this suboptimal spatial configuration is driven by a convolution of nest site fidelity and stochastic events at the level of individual nests. The resulting spatial dynamics are responsible for a hysteretic response to long-term changes in abundance. We find that declining abundance leads to fragmentation even in a homogeneous environment, which has population-level consequences for reproductive success because predation is biased towards colony edges. Strong edge effects from heterogeneous predation coupled with fragmentation in response to population declines create a positive feedback cycle that can accelerate population decline. This work provides a mechanistic understanding of complex spatial structuring in penguin colonies, provides a link between current spatial patterning and past dynamics, and suggests the possibility of critical collapse in seabird populations.

Lifetime productivity of tree cavities used by cavity-nesting animals in temperate and subtropical forests.

Tree cavities are a critical multi-annual resource that can limit populations and structure communities of cavity-nesting vertebrates. We examined the regional and local factors influencing lifetime productivity (number and richness of occupants) of individual tree cavities across two divergent forest ecosystems: temperate mixed forest in Canada and subtropical Atlantic Forest, Argentina. We predicted that (1) species would accumulate more rapidly within cavities in the species-rich system (Argentina: 76 species) than the poorer system (Canada: 31 species), (2) cavity characteristics associated with nest-site selection in short-term studies would predict lifetime cavity productivity, and (3) species would accumulate more rapidly across highly used cavities than across cavities used only once, and in Argentina than in Canada. We monitored and measured nesting cavities used by birds and mammals over 22 breeding seasons (1995-2016) in Canada and 12 breeding seasons (2006-2017) in Argentina. Cavities were used an average of 3.1 times by 1.7 species in Canada and 2.2 times by 1.4 species in Argentina. Species richness within cavities increased with number of nesting events at similar rates in Canada and Argentina, in both cases much slower than expected if within-cavity species assemblages were random, suggesting that lifetime richness of individual cavities is more strongly influenced by local ecological factors (nest site fidelity, nest niche) than by the regional species pool. The major determinant of lifetime cavity productivity was the cavity's life span. We found only weak or inconsistent relationships with cavity characteristics selected by individuals in short-term nest-site selection studies. Turnover among (vs. within) cavities was the primary driver of diversity at the landscape scale. In Canada, as predicted, species accumulation was fastest when sampling across high-use cavities. In Argentina, the rates of species accumulation were similar across high- and low-use cavities, and fastest when both high- and low-use cavities were pooled. These findings imply that biodiversity of cavity nesters is maintained by a mix of long-lived (highly productive, legacy trees) and many high-turnover (single-use, fast decaying) tree cavities. Conservation of both long-lasting and single-use cavities should be incorporated into decisions about stand-level forest management, regional land use policies, and reserve networks.

The Nesting Synchronisation Process of New Breeders in a White Stork Ciconia ciconia Colony

Many studies have focused on the colonial behaviour of birds but information on the processes related to the addition of new breeders to colonies is still scarce. The breeding parameters of new, young, breeders in a colony differ from those of experienced breeders initially. Hence, there must be an underlying process to synchronise such parameters of the new additions to the original colony values. To determine how this synchronisation process takes place, we surveyed a White Stork colony in the northern Madrid province (Spain) for five consecutive breeding seasons. Given the high nest site fidelity of this species, we established a relationship between nest age (new or old) and breeding pair age (young breeder or established adult). Newcomers occupy new nests whereas established breeders use old nests. We compared the laying dates at new nests over a 3-4 year period with those at the old nests in the colony to determine whether new breeding pairs were synchronising their laying dates to those of the existing colony. Young breeders require up to three breeding seasons to synchronise their laying dates with those of the established colony. To our knowledge, this is the first time that such a synchronisation process has been described for storks. Nest age should also be considered when analysing breeding parameters that may differ between young and old breeders. —Cabodevilla, X. & Aguirre, J.I. (2019). The nesting synchronisation process of new breeders in a White Stork Ciconia ciconia colony. Ardeola, 66: 279-289.

Improved female abundance and reproductive parameter estimates through subpopulation-scale genetic capture-recapture of loggerhead turtles

Nest counts are often used as indices for nesting female abundance in marine turtle monitoring, but accurately interpreting nest count trends requires context on the scale of demographic connectivity and estimates of reproductive parameters. Weak nest site fidelity (NSF) relative to the scale of tagging effort may bias parameter estimates. The reproductive ecology of Northern Recovery Unit (NRU) loggerhead turtles (Caretta caretta) was assessed through subpopulation-scale genetic capture-recapture via clutch sampling from approximately 1000 km of coastline from Georgia to Maryland, USA (30.75–38.06°N and 75.24–81.45°W). Of 20,682 clutches recorded from 2010 to 2012, 20,222 sampled clutches were assigned to 5684 unique females through microsatellite genotyping. Approximately 73% of females detected laying multiple clutches deposited them within a 20-km span, suggesting the possibility of demographic structuring across NRU rookeries that warrants further investigation. Estimated clutch frequencies (ECF) generated from open robust design modeling were 4.28 (4.02–4.54) in 2010, 4.63 (4.45–4.80) in 2011, and 4.57 (4.28–4.77) in 2012, and were significantly higher than observed clutch frequencies. ECF generated from single-island data were biased low by 23–50% relative to those from regional genetic tagging. Among females that nested at least once on a physical tagging beach, 54% also nested elsewhere, with 81% of these “permanently” emigrating during the nesting season. This pattern of relatively strong NSF, but distributed across multiple nearby islands, confounded modeling of detection in single-island datasets and highlights the need for regional coverage for generating robust estimates of demographic parameters for marine turtles.

Nest-Site Fidelity in Griffon Vultures: A Case of Win–Stay/Lose–Shift?

We studied the use of nest-sites by Griffon Vultures (Gyps fulvus) and the breeding success in these sites during 1998–2002 in Gamla Nature Reserve (Israel). Nest-sites in which a breeding attempt succeeded in fledging a young, were more likely to be occupied by nesting vultures in the following breeding season, than nest-sites that experienced a failure. This suggests that Griffon Vultures in Gamla used a Win–Stay/Lose–Shift strategy regarding nest-site fidelity.

Potential consequences of angling on nest-site fidelity in largemouth bass

Breeding site fidelity has evolved in many vertebrate taxa, suggesting both that site selection has an important influence on fitness potential and that the decision to reuse a nesting site is related to the individual’s prior nesting success at that location. For a species that provides parental care, such as the Largemouth Bass Micropterus salmoides, catch-and-release angling impacts individual nesting success and fitness through physiological disturbance and by removing the nest-guarding male from its brood, thereby allowing temporary access to eggs and hatchlings by brood predators. To assess the impact of catch-and-release angling on nest site fidelity, we compared the consequences of angling on individually marked (i.e., with passive integrated transponders) nest-guarding male Largemouth Bass in Ontario. An extremely high degree of nest site fidelity in year two was observed for males that were angled only once during year one (87% within 10 m of the previous year’s nest), 96.7% of which remained on the nest and completed parental care activities. There was significantly lower fidelity in year two, however, for males that were angled multiple times during year one (27% within 10m of the previous year’s nest), only 5.6% of which remained on the nest and completed parental care activities. This observed difference suggests that angling nesting bass may cause them to avoid previously used nest sites and instead search for alternative sites during future reproductive seasons. This human-induced impact on nest site choice may impact the future reproductive success of those Largemouth Bass.

Nest site fidelity of Flatback Turtles ('Natator depressus') on Bare Sand Island, Northern Territory, Australia

Nest site fidelity of Flatback Turtles ('Natator depressus') on Bare Sand Island, Northern Territory, Australia

Sex in the City: Breeding Behavior of Urban Peregrine Falcons in the Midwestern US.

Peregrine falcons (Falco peregrinus) were extirpated from most of the continental United States by widespread use of the pesticide DDT in the 1960s. Populations have rebounded with banning of the pesticide and successful implementation of captive breeding and hacking programs. An essentially new population of Midwestern peregrines now exists that is comprised almost entirely of urban-nesting birds. The new population is considered to be of mixed ancestry, occurs at relatively high densities, and has nest sites in close proximity, factors that could influence breeding behaviors including mate fidelity, nest-site fidelity, extra-pair paternity, and natal dispersal. We investigated these behaviors using a combination of field observations and DNA microsatellite genotyping. Data for eleven microsatellite DNA markers, including eight newly developed for the species, were analyzed from a total of 350 birds from nine Midwestern cities, representing 149 broods collected at 20 nest sites. To document breeding behavior, parentage was inferred by likelihood techniques when both parents were sampled and by parental genotype reconstruction when only one parent was sampled. In cases where neither parent was sampled, a sibship reconstruction approach was used. We found high mate fidelity and nest-site fidelity in urban peregrines; in 122 nesting attempts made by long-term breeders, only 12 (9.8%) mate changes and six (4.9%) nest-site changes occurred. Only one brood (of 35 tested) revealed extra-pair paternity and involved a male tending two offspring of a recently acquired mate. Natal dispersal patterns indicated that female peregrines dispersed on average 226 km, almost twice the distance of males (average 124 km). Despite the novel environment of cities, our results suggest that monogamous breeding, nest fidelity, and female natal dispersal are high in urban peregrines, not unlike other raptors living in non-urban habitats.

White-bellied Sea-Eagle breeding in the Western Port area, Victoria

The number of known active breeding sites for White-bellied Sea-Eagles Haliaeetus leucogaster in the Western Port area of Victoria has increased from one in the early 1980s to either six or seven in 2014. Three sites are located on French Island, two on Phillip Island, one at Devilbend Natural Features Reserve, Mornington Peninsula, and possibly one on Quail Island. A key factor in the increase in population is the creation and expansion of habitat reserves, especially French Island National Park, and subsequent change in management. All but one of the nests were built in tall trees. Surrounding habitats include forest, woodland, pines, farm trees and a swamp. Nest-site fidelity at several sites was low, owing to nest abandonment and collapse, with rebuilding of nests usually occurring nearby. In addition to the breeding pairs on French Island, other unpaired adult and immature Sea-Eagles are regularly observed there.

Breeding success, mate-fidelity and nest-site fidelity in Red-tailed Tropicbirds (Phaethon rubricauda) on Christmas Island, Indian Ocean

Disruption of pair-bonds and switching nest-site are associated with breeding failure in many seabirds. Both strategies can prevent repetition of poor performance with a low-quality mate or at a poor-quality nesting site. In the Red-tailed Tropicbird (Phaethon rubricauda), the relationship between mate-fidelity, nest-site fidelity and reproductive performance is poorly understood. We therefore examined this relationship in Red-tailed Tropicbirds, using data collected on Christmas Island in the Indian Ocean from 1984 to 1986, corresponding to three successive breeding seasons. Birds showed strong between-season mate-fidelity, despite previous breeding failure, and subsequent breeding success in birds faithful to their mate was significantly higher than in pairs that bred together for the first time, indicating that mate-fidelity may outweigh the costs of disruption of pair-bonds. Although switching of nest-site was more likely to occur after previous breeding failure, it did not increase subsequent breeding success, indicating that nest-site switching may not be advantageous in Red-tailed Tropicbirds on Christmas Island. Although effects of age, dispersal rates to inaccessible parts of the island and adult survival were not examined in this study, our results provide a valuable basis for the evaluation of population dynamics of Red-tailed Tropicbirds on Christmas Island.