Nest-site Fidelity Research Articles

Lay, brood, repeat: nest reuse and site fidelity in ecologic time for two Cretaceous troodontid dinosaurs

ABSTRACT—Whereas ‘biological site fidelity’ refers to the regular reuse of a favored locale (e.g., breeding ground or nest) by an individual animal, ‘paleontological site fidelity’ typically refers to repeated use of a nesting locality by a herd or species over geologic time scales. Two new Cretaceous specimens from the Two Medicine Formation of Montana, U.S.A., and the Liantoutang Formation of Zhejiang, China, each preserve two closely superimposed clutches of the egg form Prismatoolithus. These eggs belong to the Troodontidae, small theropod dinosaurs sharing a close ancestry with Aves. In both specimens, eggs of a lower clutch are truncated at a level below what would normally preserve in an undisturbed hatched clutch. These traces differ from past examples of dinosaur site fidelity in (1) the close or cross-cutting relationship of the clutches, (2) the precise overlay of clutch atop clutch, and (3) the implication of nest reuse and, thus, site fidelity on an ecologic rather than geologic scale and at approximately the individual rather than species level. Given the likely extended occupation of troodontid nesting sites by attending adults, factors such as nesting success and territoriality may, in addition to favorable substrates, have influenced the behaviors recorded by these specimens. The arrangements of eggs as clutches within the geologic record represent trace fossils. Thus, they record past in situ behavior, providing important insight into dinosaur nesting. In addition, they can serve as independent indicators of substrate conditions and sedimentary history, potentially refining our understanding of paleoenvironments.

Selección de sitios de anidación de Lepidochelys olivacea (Testudines: Cheloniidae) en el Pacífico Sur de Costa Rica

La selección del sitio de anidación en tortugas marinas es determinante para la sobrevivencia de la progenie, sin embargo para Lepidochelys olivacea existe poca información al respecto. Este trabajo se enfocó en determinar si L. olivacea selecciona sus sitios de anidación de acuerdo a un patrón o preferencia espacial determinada, o si por el contrario distribuye sus nidos aleatoriamente en la playa. La recolección de datos se realizó entre julio y setiembre del 2011, en las playas de Piro y Pejeperro, Península de Osa, Costa Rica. La ubicación del nido se evaluó midiendo las distancias entre la línea de marea y el nido, entre el nido y la vegetación, y determinando la posición del nido con respecto a los sectores marcados cada 100m en la playa. En ambas playas, las tortugas mostraron una marcada preferencia por anidar lo más lejos posible de la línea de marea, lo cual protege a sus nidos de inundación pero los expone a un mayor riesgo de depredación. Además, en playa Piro se detectó una mayor concentración de nidos cerca de la desembocadura del río, y en las cercanías de un estero en el caso de Pejeperro. Si estas zonas están asociadas a un mayor éxito de eclosión, es posible que las tortugas estén regresando y seleccionado esos sitios por impronta o filopatría. Futuras investigaciones deberán enfocarse en determinar si en eventos de anidación sucesivos, L. olivacea muestra repetibilidad y mantiene sus preferencias de anidación a nivel de individuo.

冬期におけるスズメの住宅地利用と営巣場所への執着

冬期におけるスズメの住宅地利用と営巣場所への執着

Breeding biology of the White-collared Swift Streptoprocne zonaris in southeastern Brazil

White-collared Swifts Streptoprocne zonaris are common throughout the tropical Americas. They usually breed in colonies in wet caves and next to waterfalls. Despite their widespread range, little is known about their breeding biology. Here I present data gathered from 2012 to 2014 at two breeding sites, Luminosa Cave and Agua Comprida waterfall, located within Intervales State Park, in the state of Sao Paulo, Brazil. More than 30 nests were found in the cave and one behind a waterfall. The egg-laying period began in late October and lasted until the first week of November. Nests were made mostly of bryophytes, with some fresh and dry leaves and sand. Eggs were dull white, and had an oval shape. Nestlings per nest varied from 1 to 3. The fledging period was between 41-51 days. This is the first record for this species of a successful nest with 3 nestlings. The species showed high nest site fidelity. Plumage development was similar to other species in the genus.

Strict mate fidelity and reduced breeding dispersal of widowed Red-billed Choughs Pyrrhocorax pyrrhocorax

Capsule Red-billed Choughs showed strict mate and high nest-site fidelity. Changes of mate or nesting site were recorded only in cases of widowhood or collapse of the nesting sites (buildings).Aims To evaluate the relationships between mate fidelity, nest-site fidelity, breeding dispersal and widowhood in a population of Red-billed Choughs.Methods We recorded the rates of mate and nest site fidelity in a ringed population Red-billed Choughs breeding in the Ebro Valley, NE Spain, from 1987–2006.Results We found strict mate fidelity, because no case of divorce was recorded over variable periods of mate pairing, ranging from 2 to 15 years. A proportion of widowed individuals changed nesting sites when re-paired, always establishing nests in places close to their previous nesting sites. We did not find sexual differences in the decision to change nesting site in newly paired widowed individuals, although widowed males tend to show higher site fidelity and lower breeding dispersal distances than females.Conclusions The results support the hypothesis that site fidelity primarily depends on mate fidelity, rather than the contrary. Mate and nest-site fidelity may be species-specific traits that enhance fitness through the shared knowledge of the characteristics and limitations of the mate and the territory in this long-lived species.

Reproductive parameters in the critically endangered Blue-throated Macaw: limits to the recovery of a parrot under intensive management.

Rediscovered in the wild twenty years ago, the breeding biology of wild Blue-throated Macaws remains largely unexplored, yet is essential to its effective conservation and recovery. Here, we analyse reproductive parameters in an intensively managed wild population of Blue-throated Macaws, providing the first data on the breeding biology of this critically endangered species. During the six-year study period, 2007–2012, the number of active breeding pairs either remained constant or decreased, depending on the site, and no new breeding pairs were discovered despite extensive searching. We documented nesting attempts in natural cavities in dead palms or live hardwoods, and artificial nest boxes. Egg-laying was concentrated during the end of dry season and the beginning of the wet season, August through December. Hatching failure was the greatest cause of egg losses. Half of the breeding attempts of Blue-throated Macaws produced at least one fledging, on average two, after a 85 days nestling period. An average of 4.3 nestlings per year fledged from all known wild nests combined. Each pair lost roughly 65% of its initial reproductive investment at each nesting attempt. In most successful nesting attempts of individualized pairs, a new nesting attempt was not detected the following year. All monitored breeding pairs showed high nest site fidelity, reusing hardwood-tree cavities and nest boxes. Our findings will aid conservation efforts by refining current actions and prompting new approaches towards the conservation and recovery of the Blue-throated Macaw.

Increased nesting, good survival and variable site fidelity for leatherback turtles in Florida, USA

Despite facing serious threats of extinction in the Eastern Pacific, the leatherback turtle (Dermochelys coriacea) appears to be thriving in the Atlantic basin based on increasing nest counts at several rookeries. In particular, Florida’s nest numbers have been increasing by 10.2% per year since standardized counts began in 1979. The US Recovery Plan for leatherbacks calls for vital rates and population parameters to be determined for the three leatherback rookeries under US jurisdiction: St. Croix (USVI), Puerto Rico, and the east coast of Florida. Based on mark-recapture data gathered over eleven years, we determined important population parameters for nesting female leatherbacks at Juno Beach, one of the most densely nested beaches in Florida. Average annual survival was 88.9%. The average female nesting population size for Juno Beach is estimated at 100±41 individuals each season; statewide we expect the estimate to be higher. The average remigration interval was 2.7±1.0years. In addition, we report observed clutch frequency (2.1±1.4 clutches/year), estimated clutch frequency (4.4±1.1 nests/year), and observed internesting period (10.2±1.3days between nests). The probability of observing an individual female at least once during the season was 73.0%, likely due to variable site fidelity, even though sea turtles do exhibit natal homing. Using opportunistic observations at additional beaches, we found that 72 females observed nesting within the Juno Beach study area were also observed nesting outside the study area. Thirty-three individuals laid clutches both inside and outside the survey area within a single season; these nests were separated by as much as 463.5km. Although the population in Florida is relatively small compared to other rookeries throughout the Western Atlantic, it is increasing at such a rapid pace that it has the potential to become more important regionally, thereby contributing to the abundance of leatherbacks in the Atlantic.

Abdominally implanted satellite transmitters affect reproduction and survival rather than migration of large shorebirds

Satellite telemetry has become a common technique to investigate avian life-histories, but whether such tagging will affect fitness is a critical unknown. In this study, we evaluate multi-year effects of implanted transmitters on migratory timing and reproductive performance in shorebirds. Shorebirds increasingly are recognized as good models in ecology and evolution. That many of them are of conservation concern adds to the research responsibilities. In May 2009, we captured 56 female Black-tailed Godwits Limosa limosa limosa during late incubation in The Netherlands. Of these, 15 birds were equipped with 26-g satellite transmitters with a percutaneous antenna (7.8 % ± 0.2 SD of body mass), surgically implanted in the coelom. We compared immediate nest survival, timing of migration, subsequent nest site fidelity and reproductive behaviour including egg laying with those of the remaining birds, a comparison group of 41 females. We found no effects on immediate nest survival. Fledging success and subsequent southward and northward migration patterns of the implanted birds conformed to the expectations, and arrival time on the breeding grounds in 2010–2012 did not differ from the comparison group. Compared with the comparison group, in the year after implantation, implanted birds were equally faithful to the nest site and showed equal territorial behaviour, but a paucity of behaviours indicating nests or clutches. In the 3 years after implantation, the yearly apparent survival of implanted birds was 16 % points lower. Despite intense searching, we found only three eggs of two implanted birds; all were deformed. A similarly deformed egg was reported in a similarly implanted Whimbrel Numenius phaeopus returning to breed in central Alaska. The presence in the body cavity of an object slightly smaller than a normal egg may thus lead to egg malformation and, likely, reduced egg viability. That the use of implanted satellite transmitters in these large shorebirds reduced nesting propensity and might also lead to fertility losses argues against the use of implanted transmitters for studies on breeding biology, and for a careful evaluation of the methodology in studies of migration.

An experimental study measuring the effects of a tarsus-mounted tracking device on the behaviour of a small pursuit-diving seabird

Miniaturized tracking devices are taking a rapidly increasing role in studies measuring animal movement and other aspects of behaviour, especially for wide-ranging species such as seabirds that are difficult to observe otherwise. A crucial, but questionable criterion of such migration research is assuming that effects of tracking devices on animal behaviour are negligible, to ensure results of tracking studies are biologically relevant. To address this concern, we experimentally quantified effects of a 2 g (ca. 1.1% of body mass) geolocation device on crested auklet (Aethia cristatella) behaviour, including return rate, activity on the colony surface, and measures of reproductive performance in a two-year, two-part field study. In experiment 1, we fitted tracking devices (or identical dummy devices) to one mate of a breeding pair in nesting crevices, to quantify effects on reproductive performance and nest fidelity. In experiment 2, we assigned dummy devices to birds captured at the colony site surface, to quantify effects on social activity, return rate and provisioning behaviour. For birds tagged in crevices, we detected no effect on fledging success, or chick growth rate (mass and wing length). However, mass at fledging age of chicks provisioned with one tagged parent was significantly lower than control, and low nest site fidelity (compared to control birds) was observed for tagged birds. Individuals tagged on the colony surface showed significantly reduced colony surface activity, return rates and provisioning behaviour. This study shows strong ‘observer effects’ of an attached device well below the recommended size limit for wildlife tagging. Future studies should both quantify effects of attached devices and consider the biological relevance of measures of the behaviour of interest.

Selectivity and Repeated Use of Nesting Sites in a Freshwater Turtle

Abstract: Understanding why turtles select specific localities to nest over others is important for management and conservation. For some species of freshwater turtle, the same localities are selected year upon year, but it is uncertain whether these localities are selected due to favored environmental conditions, or natal-site homing. The Mary River Turtle (Elusor macrurus) is an endangered freshwater species from Australia, and nesting data gathered between 2004 and 2011 demonstrated that female E. macrurus select to nest in specific localities along the Mary River. Here, we used time-lapse infrared photography and image-identification analysis to assess whether the same individuals returned to the same nesting banks over three consecutive years (nest-site fidelity), and we compared the physical and soil characteristics of nesting areas against other localities along the river where the turtles were not recorded to nest. The photography study illustrated that some females returned to nest at the same l...

A multievent approach to estimating pair fidelity and heterogeneity in state transitions

Fidelity rates of pair-bonded individuals are of considerable interest to behavioral and population biologists as they can influence population structure, mating rates, population productivity, and gene flow. Estimates of fidelity rates calculated from direct observations of pairs in consecutive breeding seasons may be biased because (i) individuals that are not seen are assumed to be dead, (ii) variation in the detectability of individuals is ignored, and (iii) pair status must be known with certainty. This can lead to a high proportion of observations being ignored. This approach also restricts the way variation in fidelity rates for different types of individuals, or the covariation between fidelity and other vital rates (e.g., survival) can be analyzed. In this study, we develop a probabilistic multievent capture–mark–recapture (MECMR) modeling framework for estimating pair fidelity rates that accounts for imperfect detection rates and capture heterogeneity, explicitly incorporates uncertainty in the assessment of pair status, and allows estimates of state-dependent survival and fidelity rates to be obtained simultaneously. We demonstrate the utility of our approach for investigating patterns of fidelity in pair-bonded individuals, by applying it to 30 years of breeding data from a wild population of great tits Parus major Linnaeus. Results of model selection supported state-dependent recapture, survival, and fidelity rates. Recapture rates were higher for individuals breeding with their previous partner than for those breeding with a different partner. Faithful birds that were breeding with the same partner as in the previous breeding season (i.e., at t − 1) experienced substantially higher survival rates (between t and t + 1) and were also more likely to remain faithful to their current partner (i.e., to remain in the faithful state at t + 1). First year breeders were more likely to change partner than older birds. These findings imply that traditional estimates, which do not account for state-dependent parameters, may be both inaccurate and biased, and hence, inferences based on them may conceal important biological effects. This was demonstrated in the analysis of simulated capture histories, which showed that our MECMR model was able to estimate state-dependant survival and pair fidelity rates in the face of varying state-dependant recapture rates robustly, and more accurately, than the traditional method. In addition, this new modeling approach provides a statistically rigorous framework for testing hypothesis about the causes and consequences of fidelity to a partner for natural populations. The novel modeling approach described here can readily be applied, either in its current form or via extension, to other populations and other types of dyadic interactions (e.g., between nonpaired individuals, such as parent–offspring relationships, or between individuals and locations, such as nest-site fidelity).

Living on the bare edge: fitness consequences for Cape Gannets Morus capensis at Bird Island, Algoa Bay

Avian breeding colonies often suffer high levels of predation along their margins. Nest predation is a major fitness concern for parents and therefore nests inside of the colony edge might be at a premium. This was tested through studying the colonial breeding seabird, the Cape Gannet Morus capensis, at Bird Island, Algoa Bay, South Africa. We found that breeding success is much lower for nests on the edge. Consequently, we tested whether birds nesting inside the colony had shorter foraging trips and higher nest attendance than birds along the colony edge. Although nest attendance averaged slightly less along the colony edge, the difference was not significant. Nest predation was found to be the likely cause of the higher nest failure along the colony edge. Nest positioning in Cape Gannets clearly has a profound influence on fitness, especially as the Cape Gannet appears to display a high level of nest-site fidelity.

Accounting for Imperfect Detection Is Critical for Inferring Marine Turtle Nesting Population Trends

Assessments of population trends based on time-series counts of individuals are complicated by imperfect detection, which can lead to serious misinterpretations of data. Population trends of threatened marine turtles worldwide are usually based on counts of nests or nesting females. We analyze 39 years of nest-count, female-count, and capture-mark-recapture (CMR) data for nesting loggerhead turtles (Caretta caretta) on Wassaw Island, Georgia, USA. Annual counts of nests and females, not corrected for imperfect detection, yield significant, positive trends in abundance. However, multistate open robust design modeling of CMR data that accounts for changes in imperfect detection reveals that the annual abundance of nesting females has remained essentially constant over the 39-year period. The dichotomy could result from improvements in surveys or increased within-season nest-site fidelity in females, either of which would increase detection probability. For the first time in a marine turtle population, we compare results of population trend analyses that do and do not account for imperfect detection and demonstrate the potential for erroneous conclusions. Past assessments of marine turtle population trends based exclusively on count data should be interpreted with caution and re-evaluated when possible. These concerns apply equally to population assessments of all species with imperfect detection.

Nest site fidelity and dispersal of Rio Grande wild turkey hens in Texas

AbstractRio Grande wild turkey (Meleagris gallopavo intermedia) nests suffer high predation rates exceeding 65%, which may limit recruitment. We evaluated post‐nesting movements of reproductively active female Rio Grande wild turkeys. We monitored 194 nesting attempts between 2005 and 2010 and documented 17% and 32% overall apparent nest success for the Edwards Plateau and Central Rio Grande Plains study regions, respectively. Rio Grande wild turkey hens move approximately 1.2 km (SD = 0.7) between nesting attempts within a nesting season and approximately 1.4 km (SD = 1.6) between initial nesting attempts among years. Rio Grande wild turkey hens selected open areas with moderate woody cover for nesting (${\bar {x}}$ = 37.7%; range = 3.0–88.2%). Patchiness of vegetation in the nesting landscape also was borne out by typically low edge‐to‐area ratios (${\bar {x}}$ = 0.20; range = 0.040–0.732). We found no clear pattern in movement distance and either landscape composition or edge‐to‐area ratio for within or between breeding season nest site selection for either the Edwards Plateau or Central Rio Grande Plains study region. Based on our results, movement distances post‐nest failure do not seem to influence habitat selection. © 2012 The Wildlife Society.

Migratory patterns in hawksbill turtles described by satellite tracking

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 461:223-232 (2012) - DOI: https://doi.org/10.3354/meps09778 Migratory patterns in hawksbill turtles described by satellite tracking L. A. Hawkes1,2,*, J. Tomás3,4, O. Revuelta3, Y. M. León5, J. M. Blumenthal6, A. C. Broderick4, M. Fish7, J. A. Raga3, M. J. Witt2,4, B. J. Godley4 1School of Biological Sciences, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK 2Environment and Sustainability Institute and 4Marine Turtle Research Group, Centre for Ecology and Conservation, University of Exeter, School of Biosciences, Treliever Road, Penryn, Cornwall TR10 9EZ, UK 3Marine Zoology Unit, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, PO Box 22085, Valencia 46071, Spain 5Instituto Tecnologico de Santo Domingo, Area de Ciencias Basicas, INTEC, Avenida de Los Próceres, Los Jardines del Norte 10602, Santo Domingo, Dominican Republic 6Department of the Environment, Cayman Islands Government, PO Box 10202, Grand Cayman KY1-1002, Cayman Islands 7World Wildlife Fund, 409 Granville Street, Suite 1588, Vancouver, British Columbia V6C 1T2, Canada *Email: l.hawkes@bangor.ac.uk ABSTRACT: The advent of telemetry has improved knowledge of the spatio-temporal distribution of marine species of conservation concern. Among the sea turtles, the movements of the hawksbill turtle Eretmochelys imbricata are among the least well described. We tracked 10 adult female hawksbill turtles by satellite after nesting in the Dominican Republic (DR) and describe a dichotomy in patterns of movement: some (n = 2) turtles remained in the DR, while others migrated to waters off Honduras and Nicaragua (n = 5) and the Bahamas (n = 1). Transmitters on 2 turtles failed during migration, before they reached their final foraging grounds. We present results from long tracking durations for 3 turtles, including 3 entire remigration intervals, highlighting foraging ground and nest-site fidelity. Threats to hawksbill turtles are not well documented for Nicaragua or neighbouring Honduras and represent a major information gap. We suggest that directing conservation efforts to regionally important foraging areas, such as those in Nicaragua, and strengthening national conservation in each nation with significant hawksbill nesting offers a clear way forward for the conservation of hawksbill turtles in the region. KEY WORDS: Satellite tracking · Hawksbill turtle · Caribbean · Conservation planning · Fidelity Full text in pdf format PreviousNextCite this article as: Hawkes LA, Tomás J, Revuelta O, León YM and others (2012) Migratory patterns in hawksbill turtles described by satellite tracking. Mar Ecol Prog Ser 461:223-232. https://doi.org/10.3354/meps09778 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 461. Online publication date: August 08, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Strong site fidelity and longer internesting interval for solitary nesting olive ridley sea turtles in Brazil

Olive ridley sea turtles display two different types of nesting behavior: in arribada (synchronous mass nesting) or solitarily. Contrarily to arribadas, little has been published about solitary nesters. This study aimed to expand the knowledge on internesting interval and site fidelity of solitary nesting olive ridleys and to test a possible development of arribada nesting behavior. Data were collected in Sergipe (Brazil) over 125 km of beach from 10°30′S/36o23′W to 11°26′S/37o19′W, between nesting seasons 2004/2005 and 2006/2007. From 962 tagged females, 173 were seen renesting. The average internesting interval found was longer (22.35 ± 7.01 days) than previously described, which might relate to lower water temperatures during the internesting period. Olive ridleys at Sergipe showed high nesting site fidelity, with consecutive nesting events occurring in close proximity, non-randomly and dependently of previous events. Most of the consecutive nests were separated by 4.06–5.59 km. Development of arribada nesting behavior was not confirmed.

Does breeding success lead meadow passerines to select late mown fields?

Agri-environment schemes usually assume that suitable management in patches of grassland habitat may benefit bird populations in improving the overall demographic balance. In this study, we investigate the hypothesis that nesting site fidelity after previous breeding success might lead meadow birds to select late mown fields where the risk of breeding failure is lower. It was carried out in 4 study areas of the Mezenc volcanic massif (south-east of France) within the altitude range 1,150–1,350 m. Meadow passerine territories were defined by the territory mapping method, and reproductive success in Whinchat Saxicola rubetra territories was assessed by the observation of prey carrying and juveniles just leaving nests. A comparison of models led us to consider that territorial birds selected hay fields under the influence of grass structure rather than through a theoretical successful experience of late mowing. Higher territory density was observed in fields with dense grass cover ≥50 cm which were usually more fertilized (>75 kg ha −1 nitrogen per year) and mown earlier. In 3 study sites, however, the rate of nesting failure due to mowing was lower than expected under the hypothesis of randomly distributed nesting sites, suggesting that the risk was not ignored by territorial birds. Within each study site, we also observed higher invertebrate abundance during the chick feeding period in fields with high bird territory density.

Nest site fidelity in the Slovakian population of the European pond turtle Emys orbicularis

In many places in Europe, the pond turtle Emys orbicularis (Linnaeus, 1758) is an endangered species. Establishing its reproductive pattern is critical for the understanding and protection of this turtle. In this study, which took place from 1998 to 2009 in the Tajba National Nature Reserve, Slovakia (48°23′N, 21°47′E), are presented the results concerning the spatial and temporal aspects of nesting habits of individual turtles. From the total monitored group of 39 turtles, eight individuals which laid eggs more than four times during the whole study period were selected for statistical evaluation. It was found that five individuals from this group demonstrated a fidelity to the nesting area, and that the egg-laying period starts in mid-May and continues until late June. During the investigation, six turtles nested twice per year with an interval of about 24 days. The average distance between the nests of an individual turtle was close to 138 metres, and the distance of the nests from water was about 349 metres. The data obtained on the space and time requirements of the European pond turtle for successful reproduction are helpful to protect this species more efficiently, not only in the Tajba National Natural Reserve, but also in other similar sites in Europe.

Nest-Site Fidelity and Dispersal of Gyrfalcons Estimated by Noninvasive Genetic Sampling

Abstract. We used feathers from adult Gyrfalcons (Falco rusticolus) molted in breeding territories and blood samples from nestlings to document nest-site fidelity and dispersal of breeding adults and juveniles at three areas 100– 350 km apart in Yukon Delta National Wildlife Refuge, Alaska, 2003–2007. We used genotypes from seven polymorphic microsatellite loci that provided a mean probability of identity of 0.91 × 10-5. Breeding Gyrfalcons were highly faithful to study area and territory; we documented no dispersals of breeding birds among study areas and only one dispersal between territories. But their fidelity to nest sites was low; 22% of birds returned to the same nest site the following year. Distance among alternate nests within a territory averaged 750 m and was similar for both sexes. Mean tenure in a territory was 2.8 years, similar for both sexes, and distributed bimodally with peaks at 1 and 4 years. Mean annual turnover rate at the Ingakslugwat Hills (Volcanoes) study area was 20%. We detect...

Extra-Pair Visitations to a Marbled Murrelet Nest in Northern California

Although nest prospecting, natal philopatry, and nest-site fidelity have been observed in many alcids, few data demonstrate these behaviors in Marbled Murrelets (Brachyramphus marmoratus). Prior to the 2003 breeding season, we installed a permanent video camera adjacent to a Marbled Murrelet nest site that had been used in 2001 and 2002. Video recordings in 2003 detected the simultaneous presence of 3 murrelets in alternate plumage on the nest branch, once during the incubation period, and once during the chick period. We did not observe aggression, suggesting familiarity between the extra-pair birds and site holders, and possibly avoidance of detection by predators. Without banded individuals we hypothesize extra-pair visitations at an active nest reflect nest-site prospecting, natal philopatry, or nest-site fidelity.