Chick-rearing Period Research Articles

An immune challenge induces a decline in parental effort and compensation by the mate.

Immune defense is fundamental to diminish the negative effects of the attack of infectious agents, yet the activation of the immune system entails costs and may compromise other life-history traits such as reproduction. In reproductive brown booby pairs (Sula leucogaster), we experimentally imposed an immune challenge during incubation, by intraperitoneally injecting Escherichia coli lipopolysaccharide (LPS), in either the male or the female. We aimed to test whether activation of the immune response results in (1) an increase in oxidative stress parameters, (2) a decline in post-hatching parental care in the treated individual, and (3) a compensation of the post-hatching parental effort by the nontreated mate. We found that activation of the immune response during incubation did not increase oxidative damage to lipids or total antioxidant capacity. However, mounting an immune response compromised parental effort during the chick-rearing period: compared to controls, LPS-treated parents showed roughly a 50% decline in the rate of preening and offspring feeding in response to begging. Interestingly, mates of LPS-treated parents increased their feeding rate suggesting parental care compensation. According to a scenario of full compensation, the decline in parental effort of LPS-treated parents did not result in poorer offspring growth or immune response, or increased levels of oxidative stress parameters. These findings suggest that in a long-lived species with long-lasting biparental care, an immune challenge compromises parental care, favoring parental compensation as a strategy to mitigate costs in terms of offspring success.

Occurrence of Novel and Legacy Per/Polyfluoroalkyl Substances (PFASs) in Scopoli’s Shearwater (Calonectris diomedea) Feathers

Per- and polyfluoroalkyl substances (PFASs) are contaminants of great concern due to their ubiquitous environmental occurrence in the environment and their potential adverse effects on organisms. There is currently limited information regarding the occurrence of PFASs in Scopoli’s Shearwater (Calonectris diomedea). In this study, two feather samples per bird were obtained from 26 adults on Strofades colony (Ionian Sea/Greece) during the early phase of the chick-rearing period (late July 2019). The samples consisted of barbs and barbules of the primary feathers, P1 and P10, reflecting pollution pressures at the time and the place of feather growth, i.e., at the species’ breeding and wintering grounds for P1 and P10, respectively. There were 25 PFAS detected in the feathers, with detection rates ranging from 2% (perfluorododecanoic acid—PFDoDA; perfluorohexane sulfonate—PFHxS; 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate—9Cl-PF3ONS; 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoate—Gen-X) to 98% (sodium 1H,1H,2H,2H-perfluorooctane sulfonate; 6:2 FTSA). ∑PFAS ranged from 25.93 ng/g to 426.86 ng/g of feather sample. The highest mean concentration (109.10 ng/g feather) was reported for perfluorononanoic acid (PFNA). No significant differences in PFAS concentrations with high detection rate (>20%) were found according to the sex of the birds. PFAS concentrations with a detection rate > 20% in the P1 vs. P10 feathers of Scopoli’s Shearwater adults were not significantly different, reflecting the fact that breeding grounds in the Mediterranean and wintering grounds in the Atlantic seem to be contaminated with similar PFASs levels, even though some compounds showed regional trends.

Field calibration of two survey methods to assess productivity of a ground-nesting wader, the Eurasian Curlew Numenius arquata

ABSTRACT Capsule An alternative method for estimating the hatching and fledging success of wader nests from weekly survey visits yielded higher estimates of hatching success for Eurasian Curlews than an established method that involves visits at 2–3-weekly intervals, while requiring comparable survey effort. Aims To calibrate two methods of estimating the hatching success of Eurasian Curlews based on the alarm calling behaviour of adults: an established five-visit method versus a less frequently used territory-based method that involves more frequent monitoring of individual pairs. Methods We compared estimates of hatching success from the two methods using independent surveys on the same sites. We also estimated fledging success using the territory-based method and tested whether hatching success derived from this method predicted subsequent fledging success. We quantified the approximate field effort required to deliver both methods. Results Within-site comparisons revealed that estimated hatching success was consistently higher using the territory-based method than the five-visit method, probably due to more frequent visits for the former. For the territory-based method, hatching success of individual pairs was not a reliable predictor of their subsequent fledging success, suggesting that rates of breeding failure differ between nesting and chick-rearing periods. The territory-based and five-visit methods required comparable survey days to complete per site. Conclusion The territory-based method is a useful addition to the toolkit of methods for monitoring the productivity of Eurasian Curlews and other waders. It is a more complex method to deploy and requires the identification of individual pairs, but generates what are likely to be more reliable estimates of hatching success and an additional estimate of fledging success, compared to the five-visit method.

Leach’s storm-petrel (Hydrobates leucorhous), a long-lived seabird shows flexible, condition-dependent, feeding strategies in response to poor chick condition

BackgroundParent-offspring conflict represents the sensitive balance of resource allocation between self-maintenance and reproduction. Two strategies have been proposed to better understand how species manage this conflict. In fixed-level feeding behavior, parents feed offspring consistent quantities of food; while flexible feeding shows plasticity in parental allocation based on offspring need. Life-history theory predicts that parents of long-lived species prioritize their survival and may favor the fixed-level hypothesis to maximize lifetime reproductive success. In this study, we highlight the natural variation of parent-offspring allocation strategies within a unique population of Leach’s storm-petrels (Hydrobates leucorhous), and through month-long food supplementation and restriction manipulations, we investigate how chick condition affects parental provisioning during the chick-rearing period of reproduction.ResultsWe show that the parents upregulated chick feeding frequency of nutritionally deprived chicks, resulting in a larger total amount of food delivered during the study period. Additionally, the proportion of nights when both parents fed was highest in restricted chicks, and the proportion of nights when neither parents fed was lowest in restricted chicks, suggesting that storm-petrel parents shorten their foraging bouts to deliver food more often when their chicks are in relatively poor condition.ConclusionsOur results support that Leach’s storm-petrels use a flexible-level feeding strategy, suggesting that parents can assess offspring condition, and respond by feeding chicks at higher frequencies. These data provide insight on how a long-lived seabird balances its own energetic demands with that of their offspring during the reproductive period.

Behavior and Habitat Use of Two Pairs of Red-crowned Cranes during the Chick Rearing Period in Chokubetsu, Onbetsu-cho, Kushiro, Hokkaido, Japan

Behavior and Habitat Use of Two Pairs of Red-crowned Cranes during the Chick Rearing Period in Chokubetsu, Onbetsu-cho, Kushiro, Hokkaido, Japan

Foraging behaviour and habitat use during chick-rearing in the Australian endemic black-faced cormorant (Phalacrocorax fuscescens).

Despite its wide distribution, relatively little is known of the foraging ecology and habitat use of the black-faced cormorant (Phalacrocorax fuscescens), an Australian endemic seabird. Such information is urgently required in view of the rapid oceanic warming of south-eastern Australia, the stronghold of the species. The present study used a combination of opportunistically collected regurgitates and GPS/dive behaviour data loggers to investigate diet, foraging behaviour and habitat-use of black-faced cormorants during four chick-rearing periods (2020-2023) on Notch Island, northern Bass Strait. Observed prey species were almost exclusively benthic (95%), which is consistent with the predominantly benthic diving behaviour recorded. Males foraged at deeper depths than females (median depth males: 18 m; median depth females: 8 m), presumably due to a greater physiological diving capacity derived from their larger body size. This difference in dive depths was associated with sexual segregation of foraging locations, with females predominantly frequenting shallower areas closer to the coastline. These findings have strong implications for the management of the species, as impacts of environmental change may disproportionally affect the foraging range of one sex and, thereby, reproductive success.

Intra- and interannual variation in the foraging behavior of common Murres (Uria aalge) in the Central California current

Seabirds modify their behavior during the breeding season as they transition from incubation (self-feeding) to chick-rearing (self-feeding + chick provisioning) periods, which affects parental foraging patterns and distribution. However, it is less clear how much flexibility parents have to modulate their behavior when environmental conditions are unusually poor. Using GPS loggers and time depth recorders, we examined the foraging flexibility of common murres (Uria aalge) at Southeast Farallon Island as adjustments were made between breeding phases and across consecutive years (2019 and 2020) with contrasting oceanographic conditions (i.e. prominent marine heatwave in 2019). Foraging trips were longer during the incubation period (2019: 31.7 ± 20.1 h; 2020: 23.5 ± 7.2 h) compared to the chick provisioning period (2019: 12.2 ± 9.9 h; 2020: 7.5 ± 8.3 h). Moreover, parents generally ventured farther from the colony during incubation (2019: 34.7 ± 17.6 km; 2020: 30.1 ± 11.5 km) than when foraging to provision chicks (2019: 22.6 ± 17.1 km; 2020: 14.1 ± 15.0 km) in each year. Nevertheless, overall foraging ranges had a high degree of overlap (> 60%) within breeding phases and across years, suggesting that murres at this colony are constrained by the habitats primarily based on foraging range. Murres dove deeper during incubation compared to chick-rearing in 2020 (36.0 ± 24.4 vs 19.5 ± 15.2 m), but there were no other differences within or across years in diving behavior, suggesting that diving effort was less affected by breeding stage. Interannual differences in foraging behavior only occurred during chick-feeding trips and were likely driven by the prey species present. For example, rockfish were more common in chick diets in 2020, when ocean temperatures were cooler compared to 2019. Despite similarities in trip parameters between years, breeding productivity was much lower in 2019 compared to both long-term averages and the 2020 season, suggesting a potential constraint on murre behavioral flexibility when oceanographic variation occurs. These results emphasize the importance of examining behavior on multiple time scales to gain a better understanding of how predators respond to changes in their environment.

Parental duties and foraging strategies of a tropical pelagic seabird (Phaethon aethereus, Aves: Phaethontidae) during the breeding season

Breeding seabirds must balance the energetic demands of feeding themselves and their offspring while coping with the constraints imposed by central-place foraging. As such, foraging strategies and parental care patterns are usually linked. Here, the foraging behavior of the Red-billed Tropicbird (Phaethon aethereus; n = 161) of Peña Blanca Islet, Mexico (19° 06ʹ 11ʺ N, 104° 29ʹ 12ʺ W) during the incubation and chick-rearing (≤ 4 weeks of age) stages was characterized with the aid of GPS loggers. Blood samples from adults and chicks were collected to determine δ15N and δ13C, and parental presence at the nest, meal size, and parent-chick feeding events were recorded. During incubation, parents made long trips offshore to areas far from the colony; however, immediately after their chicks hatched, the parents switched to a bimodal foraging strategy by undertaking both short and long foraging trips. The δ15N values indicated that trophic differences were present between parents and their offspring, with chicks being fed prey enriched in 15N. Parental presence at the nest was greater during early chick-rearing, which was associated with a higher provisioning rate. Parents adopted a strategy in which the parent on nest duty only made short foraging trips to provide for its offspring without leaving it unattended for long periods, while its mate undertook long trips to feed itself. After the early chick-rearing period, the parents gradually reduced the time spent at the nest and increased the time spent foraging, compensating with larger meal sizes for their offspring.Graphical abstract

Female and male body condition in the Whiskered Tern Chlidonias hybrida, a species with female offspring desertion: a test of the differential parental capacity hypothesis

AbstractOffspring desertion by a single parent, mainly the female, occurs in many charadriiform birds. According to the differential parental capacity hypothesis (DPCH), females are more likely to desert, since they may be in poorer body condition than males as a consequence of egg-laying costs. This study investigated the body condition of 122 male and 118 female Whiskered Terns. In this species half of females desert during the chick-rearing period, the remainder during the post-fledging period. Body condition was investigated during the late incubation and early chick-rearing phases during the biparental care period in: (1) females that deserted during the chick-rearing period, (2) females that did not desert during this time, (3) males deserted by females, and (4) males not deserted by females. Among females that stayed, body condition during the pre-hatching period did not vary with relative catching date (clutch/brood age), whereas females that later deserted showed a very poor body condition when caught around seven days prior to hatching. After hatching, body condition was lower in both deserting and non-deserting females caught later. Among males whose females stayed, body condition remained nearly stable, whereas the body condition of males whose females deserted was lower the later they were caught. These results tally only partially with the DPCH: the pattern of parental body condition changes during breeding is apparently more complex than assumed by the DPCH and the cost of egg laying may be lower than suggested. Desertion by Whiskered Tern females is better explained by the sex role differences in parental care. The male’s ability to compensate for the missing female may be playing a role in the evolution of desertion.

Investigating two consecutive catastrophic breeding seasons in a large king penguin colony

Large-scale breeding failures, such as offspring die-offs, can disproportionately impact wildlife populations that are characterized by a few large colonies. However, breeding monitoring—and thus investigations of such die-offs—is especially challenging in species with long reproductive cycles. We investigate two unresolved dramatic breeding failures that occurred in consecutive years (2009 and 2010) in a large king penguin Aptenodytes patagonicus colony, a long-lived species with a breeding cycle lasting over a year. Here we found that a single period, winter 2009, was likely responsible for the occurrence of breeding anomalies during both breeding seasons, suggesting that adults experienced poor foraging conditions at sea at that time. Following that unfavorable winter, the 2009 breeding cohort—who were entering the late stage of chick-rearing—immediately experienced high chick mortality. Meanwhile, the 2010 breeding cohort greatly delayed their arrival and egg laying, which would have otherwise started not long after the winter. The 2010 breeding season continued to display anomalies during the incubation and chick-rearing period, such as high abandonment rate, long foraging trips and eventually the death of all chicks in winter 2010. These anomalies could have resulted from either a domino-effect caused by the delayed laying, the continuation of poor foraging conditions, or both. This study provides an example of a large-scale catastrophic breeding failure and highlights the importance of the winter period on phenology and reproduction success for wildlife that breed in few large colonies.

The effect of climate change on avian offspring production: A global meta-analysis

Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring. Likewise, multi-brooded species showed increased breeding success with increasing temperatures, whereas rising temperatures were unrelated to reproductive success in single-brooded species. Our study suggests that rapid declines in size of bird populations reported by many studies from different parts of the world are driven only to a small degree by changes in the production of young.

High-resolution recording of foraging behaviour over multiple annual cycles shows decline in old Adélie penguins' performance.

Age-related variation in foraging performance can result from both within-individual change and selection processes. These mechanisms can only be disentangled by using logistically challenging long-term, longitudinal studies. Coupling a long-term demographic data set with high-temporal-resolution tracking of 18 Adélie penguins (Pygoscelis adeliae, age 4-15 yrs old) over three consecutive annual cycles, we examined how foraging behaviour changed within individuals of different age classes. Evidence indicated within-individual improvement in young and middle-age classes, but a significant decrease in foraging dive frequency within old individuals, associated with a decrease in the dive descent rate. Decreases in foraging performance occurred at a later age (from 12-15 yrs old to 15-18 yrs old) than the onset of senescence predicted for this species (9-11 yrs old). Foraging dive frequency was most affected by the interaction between breeding status and annual life-cycle periods, with frequency being highest during returning migration and breeding season and was highest overall for successful breeders during the chick-rearing period. Females performed more foraging dives per hour than males. This longitudinal, full annual cycle study allowed us to shed light on the changes in foraging performance occurring among individuals of different age classes and highlighted the complex interactions among drivers of individual foraging behaviour.

Quantifying annual spatial consistency in chick-rearing seabirds to inform important site identification

Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed area-based conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track animals in multiple years to capture changes in distribution in response to varying environmental conditions. Using GPS-tracking data from 23 seabird species, we assessed the importance of multi-year sampling for identifying important sites for conservation during the chick-rearing period, when seabirds are most spatially constrained. We found a high degree of spatial overlap among distributions from different years in most species. Multi-year sampling often captured a significantly higher portion of reference distributions (based on all data for a population) than sampling in a single year. However, we estimated that data from a single year would on average miss only 5 % less of the full distribution of a population compared to equal-sized samples collected across three years (min: −0.3 %, max: 17.7 %, n = 23). Our results suggest a key consideration for identifying important sites from tracking data is whether enough individuals were tracked to provide a representative estimate of the population distribution during the sampling period, rather than that tracking necessarily take place in multiple years. By providing an unprecedented multi-species perspective on annual spatial consistency, this work has relevance for the application of tracking data to informing the conservation of seabirds.

Do females of Whiskered Tern Chlidonias hybrida renest after offspring desertion?

In species with biparental care, one parent may relieve him-/herself of the costs of parental care by deserting and leaving the mate to care for the offspring. Offspring desertion by a single parent, usually the female, occurs in many bird species, especially in Charadriiformes. The reasons for desertion are still being debated, and compelling evidence for the benefits and costs to either sex is not yet handed. The benefits of desertion for the deserter may include renesting with a new mate shortly after desertion. Therefore, desertion may enhance individual lifetime reproductive success. In Whiskered Tern Chlidonias hybrida almost all females desert, about half of females desert during chick-rearing period, the other half during the post-fledging period. Based on intensive fieldwork over a 4-year study, we investigated whether Whiskered Tern females remated and renested after desertion. We assumed that favourable conditions, such as an extended breeding season and food abundance resulting in a high breeding success would prompt most females to renest after desertion. In contrast to this expectation, however, only 5% of females that deserted during chick-rearing period (2 out of 41) remated and renested in the study area. About 50 days elapsed between the initiations of the first and second clutch by these two females. Females also participated in courtship behaviour after desertion (without renesting). We thus estimate that 15% (6 out of 41) of females that deserted during chick-rearing period were subsequently involved in some kind of breeding activity. Therefore, renesting does not seem to be a major direct benefit for deserting Whiskered Tern females. Females of this species probably benefit from desertion in other ways, but these have yet to be discovered.

Implications of Regurgitative Feeding on Plastic Loads in Northern Fulmars (Fulmarus glacialis): A Study from Svalbard.

Procellariiform seabirds like northern fulmars (Fulmarus glacialis) are prone to ingest and accumulate floating plastic pieces. In the North Sea region, there is a long tradition to use beached fulmars as biomonitors for marine plastic pollution. Monitoring data revealed consistently lower plastic burdens in adult fulmars compared to younger age classes. Those findings were hypothesized to partly result from parental transfer of plastic to chicks. However, no prior study has examined this mechanism in fulmars by comparing plastic burdens in fledglings and older fulmars shortly after the chick-rearing period. Therefore, we investigated plastic ingestion in 39 fulmars from Kongsfjorden (Svalbard), including 21 fledglings and 18 older fulmars (adults/older immatures). We found that fledglings (50-60 days old) had significantly more plastic than older fulmars. While plastic was found in all fledglings, two older fulmars contained no and several older individuals barely any plastic. These findings supported that fulmar chicks from Svalbard get fed high quantities of plastic by their parents. Adverse effects of plastic on fulmars were indicated by one fragment that perforated the stomach and possibly one thread perforating the intestine. Negative correlations between plastic mass and body fat in fledglings and older fulmars were not significant.

Home range variability and philopatry in Cinereous vultures (Aegypius monachus) breeding in Iberia

Large scavengers are strongly dependent on environmental conditions and carrion distribution and abundance, so season and breeding-related factors may influence the spatial ecology of species such as the Cinereous Vulture (Aegypius monachus), the largest European raptor. Iberia holds one of the biggest populations worldwide, but some aspects of the spatial ecology of the species in this region remain unknown. In this study, 17 adult Cinereous Vultures were GPS-tracked in order to study their spatial ecology during the adult phase. The average monthly home ranges (95% Kernel Density Estimation, KDE) and core areas (50% KDE) were 6543 ​± ​19,935 ​km2 and 1174 ​± ​4004 ​km2, respectively. The average monthly home range fidelity ranged between 50 and 73%. Differences in movement-related variables between the seasonal periods (incubation, chick-rearing and non-breeding) were found. During the chick-rearing period, the monthly accumulated distance was higher than during the other periods: 3316 ​± ​1108 (chick-rearing) vs. 1621 ​± ​622 (incubation) vs. 1726 ​± ​1159 ​km per month (non-breeding). Additionally, large home range sizes were more frequent during the chick-rearing period. There are two likely causes for these seasonal differences. Firstly, chick-rearing entails a higher energetic expenditure by the parental individuals in foraging activities, so larger movements and foraging areas are expected during this period. Secondly, the flight is favoured during spring and summer due to environmental conditions. Matching chick-rearing and warm months is a great evolutionary advantage for soaring-gliding raptors, as it allows them to cover larger areas with low energy expenditure. Furthermore, six individuals tagged as nestlings highlight the philopatric behaviour of the species: vultures settle their breeding areas 54 ​± ​51 ​km from their natal nest (range ​= ​9–138 ​km).

Inter-colony variation in the foraging behaviour and resource selection of breeding Herring Gulls Larus argentatus

The resources available to breeding seabirds within their foraging ranges can influence productivity, either directly through the quality and quantity of food consumed by chicks, or indirectly by affecting the foraging behaviour and efficiency of parent birds. Where local resource availability is low, or the quality of resources are poor, species with flexible time-energy budgets can increase their foraging effort to provide adequate energy and nutrients to their chicks, although this may come at the expense of nest attendance. We investigated provisioning rates and nest attendance in European Herring Gulls Larus argentatus from seven colonies across southwest Scotland and Northern Ireland during two chick-rearing periods (2013 and 2014) in relation to the food resources used by these colonies. We observed variation in provisioning rates and nest attendance between colonies, and variation between years in nest attendance. We found no significant relationships between these behaviours and the proportion of intertidal prey consumed, suggesting that provisioning rate and nest attendance did not differ between resource types at the colony level. We also found no evidence that variation in behaviours was related to breeding success. Our results suggest that, within this region, the type of resources consumed had a greater influence on Herring Gull breeding success than differences in two proxies of foraging efficiency (provisioning rate and nest attendance), although other factors may also have influenced breeding success. Our work highlights the benefit of determining what food resources are provided to chicks, in addition to measuring foraging behaviours, to fully understand the consequences of consuming different resources on the breeding success of generalist foragers.

Characteristics of Great Bustard (Otis tarda) (Otididae, Aves) Habitats in the Trans-Volga Region according to Food Availability during the Chick Rearing Period

Characteristics of Great Bustard (Otis tarda) (Otididae, Aves) Habitats in the Trans-Volga Region according to Food Availability during the Chick Rearing Period

Surveying cliff-nesting seabirds with unoccupied aircraft systems in the Gulf of Alaska

Drones, or unoccupied aircraft systems (UAS), can transform the way scientific information on wildlife populations is collected. UAS surveys produce accurate estimates of ground-nesting seabirds and a variety of waterbirds, but few studies have examined the trade-offs of this methodology for counting cliff-nesting seabirds. In this study, we examined how different UAS survey parameters might influence seabird counts for population monitoring and assessed behavioral responses to aerial surveys for three sub-Arctic seabird taxa in the Gulf of Alaska: common murres (Uria aalge), black-legged kittiwakes (Rissa tridactyla), and pelagic and double-crested cormorants (Phalacrocorax pelagicus and Phalacrocorax auritus). We flew two commercially available models of UAS in planned approaches at different speeds and distances from colonies during incubation and chick-rearing periods. We compared counts from UAS-derived images with those from vessel-based photography and assessed video recordings of individual birds’ behaviors for evidence of disturbance during UAS operations and control phases. Count estimates from UAS images were similar to or higher than those from conventional vessel-based images, and UAS were particularly effective at photographing birds at sites with high cliff walls or complex topography. We observed no significant behavioral responses to the UAS by murres or cormorants, but we did observe flushing by black-legged kittiwakes during UAS flights; most of these birds were not incubating or brooding. At both the colony and individual level, we observed slightly greater responses to the smaller UAS platform and closer approaches. These results inform both species specific and general best practices for research and recreational usage of UAS near cliff-nesting seabird colonies.

Reproductive Success of Red-Billed Tropicbirds (Phaethon aethereus) on St. Eustatius, Caribbean Netherlands

The daily nest-survival rates of Red-billed Tropicbirds (Phaethon aethereus) were estimated over six breeding seasons on St. Eustatius in the Caribbean. We analyzed 338 nesting attempts between 2013 and 2020. The daily survival rate (DSR) of tropicbird nests was modeled as a function of nest initiation date, sea surface temperature (SST), elevation, vegetation in front of the nest, and year. Yearly nest survival rates (± SE) of the best fitting models ranged from 0.21 ± 0.06–0.74 ± 0.13 (n = 338 nests). DSR of the most parsimonious models averaged 0.39 ± 0.04 during the incubation period, 0.83 ± 0.05 during the chick-rearing period, and 0.30 ± 0.04 during the nesting period (incubation through fledging) when data were pooled across all years. Models with linear and quadratic trends of nest initiation date combined with SST and elevation received strong support in the incubation and nesting periods. Nests initiated in peak nesting season, when SSTs were lower, had higher DSR estimates than nests initiated early or late in the season. Compared to studies of the same species from Saba and the Gulf of California, survival probability on St. Eustatius was lower during the incubation stage but higher during the chick-rearing period. Similar to populations in the Gulf of California, tropicbird reproduction differed and laying date varied among years, and survival was influenced by SST. Our results are consistent with a study on White-tailed Tropicbirds (Phaethon lepturus) in Bermuda which found that survival was affected by temporal factors rather than physical site characteristics. Our study contributes to a better understanding of the factors that influence Red-billed Tropicbird survival on a small Caribbean island.