Search USGS⌕ Search

Geology topics

Patrick G.R. Jodice

Publications and source records attributed to Patrick G.R. Jodice.

At least 37 records · Page 2Linked to original sources
USGS2022

Seabird vulnerability to oil: Exposure potential, sensitivity, and uncertainty in the northern Gulf of Mexico

The northern Gulf of Mexico (nGoM) is a globally important region for oil extraction and supports a diverse assemblage of marine birds. Due to their frequent contact with surface waters, diverse foraging strategies, and the ease with which oil adheres to feathers, seabirds are particularly susceptible to hydrocarbon contamination. Given the chronic and acute exposure of seabirds to oiling and a lack of studies that focus on the exposure of seabirds to oiling in sub-tropical and tropical regions, a greater understanding of the vulnerability of seabirds to oil in the nGoM appears warranted. We present an oil vulnerability index for seabirds in the nGoM tailored to the current state of knowledge using new, spatiotemporally expensive vessel-based seabird observations. We use information on the exposure and sensitivity of seabirds to oil to rank seabird vulnerability. Exposure variables characterized the potential to encounter oil and gas (O&G). Sensitivity variables characterized the potential impact of seabirds interacting with O&G and are related to life history and productivity. We also incorporated uncertainty in each variable, identifying data gaps. We found that the percent of seabirds’ habitat defined as highly suitable within 10 km of an O&G platform ranged from 0%-65% among 24 species. Though O&G platforms only overlap with 15% of highly suitable seabird habitat, overlap occurs in areas of moderate to high vulnerability of seabirds, particularly along the shelf-slope. Productivity-associated sensitivity variables were primarily responsible for creating the gradient in vulnerability scores and had greater uncertainty than exposure variables. Highly vulnerable species (e.g., Northern gannet ( Morus bassanus )) tended to have high exposure to the water surface via foraging behaviors (e.g., plunge-diving), older age at first breeding, and an extended incubating and fledging period compared to less vulnerable species (e.g., Pomarine jaeger ( Stercorarius pomarinus )). Uncertainty related to productivity could be reduced through at-colony monitoring. Strategic seabird satellite tagging could help target monitoring efforts to colonies known to use the nGoM, and continued vessel-based observations could improve habitat characterization. As offshore energy development in the nGoM continues, managers and researchers could use these vulnerability ranks to identify information gaps to prioritize research and focal species.

northern Gulf of Mexico↗
USGS2022

Urban proximity while breeding is not a predictor of perfluoroalkyl substance contamination in the eggs of brown pelicans

Identifying sources of exposure to chemical stressors is difficult when both target organisms and stressors are highly mobile. While previous studies have demonstrated that populations of some organisms proximal to urban centers may display increased burdens of human-created chemicals compared to more distal populations, this relationship may not be universal when applied to organisms and stressors capable of transboundary movements. We examined eggs of brown pelicans ( Pelecanus occidentalis ), a nearshore seabird with daily movements ranging from local to 50 km and annual migrations ranging from year-round residency to 1500 km. Thirty-six eggs from three breeding colonies located at increasing distances to a major urban center (Charleston, South Carolina, USA) were analyzed for concentrations of per - and polyfluoroalkyl substances (PFAS). Areas of high use for each colony during the breeding season were also assessed via the tracking of adult pelicans from each colony using GPS-PTT satellite transmitters and overlapped with measures of relative urbanization via land cover data. We report potentially significant ∑PFAS concentrations in the eggs of pelicans (175.4 ± 120.1 ng/g w wt. SD), driven largely by linear perfluorooctane sulfonate (n-PFOS) (48–546 ng/g w wt.). Residues of the precursor compound perfluorooctane sulfonamide (FOSA) were also present in pelican eggs, suggesting continued exposure of local wildlife beyond implemented phaseouts of some PFAS. For most analytes, egg concentrations did not exhibit a significant spatial structure despite some differentiation in high-use areas unlike similar data for another regional apex predator, the bottlenose dolphin ( Tursiops truncatus ). We suggest that the partially migratory nature of brown pelicans during the non-breeding season, combined with daily ranges that may extend to 50 km from local point sources, may have homogenized exposure across individuals. Charleston likely remains a major source for PFAS in the overall region, however, given the high concentrations observed as well as known releases of PFAS in the nearshore environment.

South Carolina↗
USGS2022

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.

Waterbirds↗
USGS2022

Interannual colony exchange among breeding Eastern Brown Pelicans

Colonial seabirds often display high rates of interannual site fidelity to breeding locations, especially as adults. Species using more nearshore or coastal systems, however, may display comparatively less fidelity than highly pelagic species. We used long-term GPS tracking data to assess the frequency of interannual colony switching in Eastern Brown Pelicans ( Pelecanus occidentalis carolinensis ) in the South Atlantic Bight, a species about which adult site fidelity is poorly understood. By using recursive behavioral patterns to identify nest locations, we report 36% of reproductive attempts occurred at colonies that were different from the colony used in a prior year. Colony switching was especially prevalent in female pelicans, and distances between switched colonies ranged from 56 to 592 km. We suggest that long-term telemetry may be a reliable tool for assessing interannual breeding site fidelity, especially when compared to more traditional band resighting efforts.

Georgia, South Carolina↗
USGS2022

Foraging ecology of Red-billed Tropicbird Phaethon aethereus in the Caribbean during early chick rearing revealed by GPS tracking

Investigating the foraging patterns of tropical seabirds can provide important information about their ocean habitat affinities as well as prey choice. Foraging studies of Red-billed Tropicbird Phaethon aethereus populations in the Caribbean are lacking. We sought to rectify this by opportunistically sampling regurgitates at nest sites on the island of St. Eustatius, Lesser Antilles, and by linking the GPS tracks of foraging adults to remotely sensed environmental variables. Diet samples were dominated by Exocoetidae (59.5%) and Belonidae (14.9%), although we were unable to identify 25.5% of samples due to digestion. Tropicbirds nesting on St. Eustatius exhibited diurnal foraging patterns, foraged in deeper waters with higher chlorophyll concentration, and consumed fewer Exocoetidae species compared to travelling behaviour. The maximum distance travelled from the colony was 953.7 km, with an average trip length of 176.8 (± 249.8) km. The biologged birds crossed multiple exclusive economic zones and marine protected areas, and on that basis, we suggest that efforts to protect and conserve this species may require transboundary collaboration throughout the wider Caribbean.

Marine Ornithology: Journal of Seabird Research an↗
USGS2021

Cooperative Fish and Wildlife Research Units program—2020 Year in review

Established in 1935, the Cooperative Fish and Wildlife Research Units program (CRU program) is a unique cooperative partnership among State fish and wildlife agencies, universities, the Wildlife Management Institute, the U.S. Geological Survey (USGS), and the U.S. Fish and Wildlife Service. Designed to meet the scientific needs of natural resource management agencies and the necessity for trained professionals in the growing field of wildlife management, the program has grown from the original 9 wildlife-only units to a program that today includes 40 Cooperative Fish and Wildlife Research Units located on university campuses in 38 States. The partnerships that form each unit are some of the USGS’s strongest links to Federal and State land and natural resource agencies as mandated by the Cooperative Research and Training Units Act of 1960 (P.L. 86–686). This report highlights the activities and accomplishments of the program and its cooperators for calendar year 2020.

Circular↗
USGS2021

Revising the marine range of the endangered black-capped petrel Pterodroma hasitata: occurrence in the northern Gulf of Mexico and exposure to conservation threats

The black-capped petrel Pterodroma hasitata is an Endangered seabird endemic to the western North Atlantic. Although estimated at ~1000 breeding pairs, only ~100 nests have been located at 2 sites in Haiti and 3 sites in the Dominican Republic. At sea, the species primarily occupies waters of the western Gulf Stream in the Atlantic and the Caribbean Sea. Due to limited data, there is currently no consensus on the geographic marine range of the species although no current proposed ranges include the Gulf of Mexico. Here, we report on observations of black-capped petrels during 2 vessel-based survey efforts throughout the northern Gulf of Mexico from 2010-2011 and 2017-2019. During 558 d and ~54700 km of surveys, we tallied 40 black-capped petrels. Most observations occurred in the eastern Gulf, although birds were observed over much of the east-west and north-south footprint of the survey area. Predictive models indicated that habitat suitability for black-capped petrels was highest in areas associated with dynamic waters of the Loop Current. We used the extent of occurrence and area of occupancy concepts to delimit the geographic range of the species within the northern Gulf. We suggest that the marine range for black-capped petrels be modified to include the northern Gulf of Mexico, recognizing that distribution may be more clumped in the eastern Gulf and that occurrence in the southern Gulf remains unknown due to a lack of surveys there. To date, however, it remains unclear which nesting areas are linked to the Gulf of Mexico.

Northern Gulf of Mexico↗
USGS2021

Fine-scale weather patterns drive reproductive success in the Brown Pelican

In the northern Gulf of Mexico, island restoration and creation have been used to mitigate potential negative effects of anthropogenic and environmental stressors to breeding seabirds. The long-term success of such projects can be enhanced when data are available to elucidate how site-specific and larger-scale factors may contribute to reproductive success. Nest-specific daily survival rate (DSR) of Eastern Brown Pelicans ( Pelecanus occidentalis carolinensis ) during incubation (i.e., pre-hatch; n = 245) and brood-rearing (i.e., post-hatch; n = 185) were measured at two breeding islands in the northern Gulf of Mexico USA in 2017 and 2018 in relation to macro- and micro- scale habitat and environmental measurements. DSR of nests during incubation ranged from 91-99%, and the DSR during brood-rearing exceeded 99% each year. Regional weather variables occurred in top-performing models more often and with more significance compared to microhabitat variables. Results suggest that reproductive success of Brown Pelicans may respond at least in part to weather factors that occur outside of the scope of habitat structure as it is typically incorporated into the restoration or creation of breeding habitat, indicating that climate conditions are likely an important factor in the success of restoration efforts.

Alabama↗
USGS2021

Spatial and temporal overlap between foraging shorebirds and spawning horseshoe crabs (Limulus polyphemus) in the Cape Romain-Santee Delta Region of the U.S. Atlantic coast

Shorebird use of horseshoe crab ( Limulus polyphemus ) eggs as food items has been well documented along the Atlantic coast of the United States at northeastern stopover sites such as the Delaware Bay. However, the relationship between migratory shorebirds and horseshoe crab eggs has not been well studied in the South Atlantic Bight. The objective of our study was to assess the spatial and temporal overlap between the density of horseshoe crab eggs and the relative abundance of foraging shorebirds during spring migration in the Cape Romain-Santee Delta Region (CRSD), South Carolina, USA. The CRSD is a site of international importance for shorebirds that supports ∼100,000 shorebirds annually. We also sought to determine if horseshoe crab eggs were present in the diets of shorebirds at these sites. We monitored study plots between March and June 2015–2016 at predicted horseshoe crab spawning sites on beaches throughout Cape Romain National Wildlife Refuge. We conducted weekly shorebird surveys and collected core samples of beach substrate twice per month to measure densities of horseshoe crab eggs. We found a positive correlation between number of foraging shorebirds and horseshoe crab eggs for both years. In a molecular analysis of shorebird fecal samples, 95% of the samples tested contained DNA from horseshoe crab eggs. The spatial and temporal overlap between shorebirds and horseshoe crab eggs, and the dietary analysis of fecal samples, suggest that there are areas of localized horseshoe crab spawning that shorebirds can utilize as a food source during spring in Cape Romain National Wildlife Refuge.

South Carolina↗
USGS2021

Post-release survival of California brown pelicans (Pelecanus Occidentalis Californicus) following oiling and rehabilitation after the Refugio oil spill

Oil spills represent a continued threat to marine wildlife. Although the public expects, and the State of California, US requires, oiled animals to be rescued for rehabilitation and release, scientists have questioned the welfare and conservation value of capture and rehabilitation of oiled wildlife, based on poor postrelease survival documented in the few available studies. In May 2015, Plains Pipeline 901 spilled >100,000 gallons of oil near Refugio State Beach, California. Many California Brown Pelicans ( Pelecanus occidentalis californicus ) were oiled; capture and rehabilitation efforts began within 1 d. Ultimately, 65 live birds were captured, including 50 pelicans. Forty-six pelicans survived and were released. Of these, 12 adults (six male, six female) were fitted with solar-powered GPS satellite Platform Terminal Transmitters (PTT) and released in June 2015. In early July, we captured eight adult (three male, four female, one unknown), unoiled pelicans from the Ventura, California area. These control birds were similarly instrumented and released immediately. At 6 mo after release, PTTs from nine of 12 oiled pelicans and six of eight control pelicans were still transmitting; at 1 yr, those numbers decreased to two of 12 and two of eight, respectively. Survival analysis revealed no difference in survival between oiled and control birds. Although our sample size is limited, these data demonstrate that most oiled and rehabilitated pelicans can survive for 6 mo following release, and some individuals can survive over 1 yr.

California↗
USGS2020

Habitat modelling locates nesting areas of the endangered Black-capped Petrel Pterodroma hasitata on Hispaniola and identifies habitat loss

The Black-capped Petrel or Diablotin Pterodroma hasitata has a fragmented and declining population estimated at c.1,000 breeding pairs. On land, the species nests underground in steep ravines with dense understorey vegetation. The only confirmed breeding sites are located in the mountain ranges of Hispaniola in the Caribbean, where habitat loss and degradation are continuing threats. Other nesting populations may still remain undiscovered but, to locate them, laborious in situ nest searches must be conducted over expansive geographical areas. To focus nest-search efforts more efficiently, we analysed the environmental characteristics of Black-capped Petrel nesting habitat and modeled suitable habitat on Hispaniola using openly available environmental datasets. We used a univariate generalized linear model to compare the habitat characteristics of active Black-capped Petrel nests sites with those of potentially available sites (i.e. random pseudo-absences). Elevation, distance to coast, and the influence of tree cover and density emerged as important environmental variables. We then applied multivariate generalized linear models to these environmental variables that showed a significant relationship with petrel nesting activity. We used the top performing model of habitat suitability model to create maps of predicted suitability for Hispaniola. In addition to areas of known petrel activity, the model identified possible nesting areas for Black-capped Petrels in habitats not previously considered suitable. Based on model results, we estimated the total area of predicted suitable nesting habitat for Black-capped Petrels on Hispaniola and found that forest loss due to hurricanes, forest fires, and encroachment from agriculture had severely decreased availability of predicted suitable habitat between 2000 and 2018.

Hispaniola↗
USGS2020

Ultraviolet-assisted oiling assessment improves detection of oiled birds experiencing clinical signs of hemolytic anemia after exposure to the Deepwater Horizon oil spill

While large-scale oil spills can cause acute mortality events in birds, there is increasing evidence that sublethal oil exposure can trigger physiological changes that have implications for individual performance and survival. Therefore, improved methods for identifying small amounts of oil on birds are needed. Because ultraviolet (UV) light can be used to identify thin crude oil films in water and on substrate that are not visually apparent under normal lighting conditions, we hypothesized that UV light could be useful for detecting small amounts of oil present on the plumage of birds. We evaluated black skimmers ( Rynchops niger ), brown pelicans ( Pelecanus occidentalis ), clapper rails ( Rallus crepitans ), great egrets ( Ardea alba ), and seaside sparrows ( Ammodramus maritimus ) exposed to areas affected by the Deepwater Horizon oil spill in the Gulf of Mexico as well as from reference areas from 20 June, 2010 to 23 February, 2011. When visually assessed without UV light, 19.6% of birds evaluated from areas affected by the spill were determined to be oiled (previously published data), whereas when examined under UV light, 56.3% of the same birds were determined to have oil exposure. Of 705 individuals examined in areas potentially impacted by the spill, we found that fluorescence under UV light assessment identified 259 oiled birds that appeared to be oil-free on visual exam, supporting its utility as a simple tool for improving detection of modestly oiled birds in the field. Further, UV assessment revealed an increase in qualitative severity of oiling (approximate % of body surface oiled) in 40% of birds compared to what was determined on visual exam. Additionally, black skimmers, brown pelicans, and great egrets exposed to oil as determined using UV light experienced oxidative injury to erythrocytes, had decreased numbers of circulating erythrocytes, and showed evidence of a regenerative hematological response in the form of increased reticulocytes. This evidence of adverse effects was similar to changes identified in birds with oil exposure as determined by visual examination without UV light, and is consistent with hemolytic anemia likely caused by oil exposure. Thus, UV assessment proved useful for enhancing detection of birds exposed to oil, but did not increase detection of birds experiencing clinical signs of anemia compared to standard visual oiling assessment. We conclude that UV light evaluation can help identify oil exposure in many birds that would otherwise be identified visually as unexposed during oil spill events.

Ecotoxicology↗
USGS2020

Spatial ecology of closely-related taxa: The case of the little shearwater complex in the North Atlantic Ocean

Seabirds inhabiting vast water masses provide numerous examples where opposing phenomena, such as natal and breeding philopatry vs. vagility have dug cryptic taxonomic boundaries among closely related taxa. The taxonomy of little shearwaters of the North Atlantic Ocean (Little–Audubon’s shearwater complex, Puffinus assimilis – lherminieri ) still remains unclear, and complementary information on non-breeding distributions and at-sea behaviour becomes essential to unravel divergent local adaptations to specific habitats. Using miniaturized light-level geolocators from seven study areas in the North Atlantic, we evaluate the spatial and habitat segregation, estimate the timing of their key life-cycle events and describe the at-sea behaviour of three taxa of these little shearwaters year-round to distinguish ecological patterns and specializations that could ultimately unravel potential lineage divergences. We also assess morphometric data from birds that were breeding at each study area to further discuss potential adaptations to specific habitats. Our results show that, while birds from different taxa segregated in space and habitats, they share ecological plasticity, similar annual phenology and diel foraging behaviour. These ecological inconsistencies, while defining the evolutionary stressors faced by these taxa, do not suggest the existence of three Evolutionary Significant Units. However, they confirm the recent evolutionary divergence among the three little shearwaters of the North Atlantic.

Zoological Journal of the Linnean Society↗
USGS2020

High spatial fidelity among foraging trips of Masked Boobies from Pedro Cays, Jamaica

In marine environments, tropical and subtropical habitats are considered to be inherently less productive than more temperate systems. As such, foraging site fidelity among vertebrate predators occupying low-latitude marine systems is generally low as a response to an increased unpredictability of resources. We investigated the foraging movements of Masked Boobies breeding on Middle Cay, Jamaica using GPS loggers to examine if the presence of a nearby bathymetric feature influenced foraging site fidelity in a tropical system, the Caribbean Sea. According to the movements of tracked individuals, this population of boobies shows a high degree of spatial fidelity in foraging site selection, concentrated on the northern edge of Pedro Bank. We suggest this feature as an important location for marine conservation in the region and demonstrate its utility to foraging boobies via habitat modeling using a maximum entropy approach of relevant habitat variables. Finally, we place this study into the global context of Masked Booby foraging by examining the published literature of relevant tracking studies for population-level similarity in foraging metrics. According to hierarchical clustering of foraging effort, Masked Boobies demonstrate a density-dependent response to foraging effort regardless of colony origin or oceanic basin consistent with the principles of Ashmole’s Halo.

Middle Cay, Pedro Bank↗
USGS2020

Mercury, cadmium, copper, arsenic, and selenium measurements in the feathers of adult eastern brown pelicans (Pelecanus occidentalis carolinensis) and chicks in multiple breeding grounds in the northern Gulf of Mexico

The amounts of trace metals and metalloids that have been introduced into aquatic ecosystems due to anthropogenic activities have increased in recent decades. Some of these elements like mercury are easily transferred from one trophic level to another and can accumulate to toxic quantities in organisms at the top of aquatic food webs. For this reason, seabirds like the Eastern brown pelican (Pelecanus occidentalis carolinensis ) are susceptible to heavy metal and metalloid toxicity and may warrant periodic monitoring. Mercury, cadmium, copper, arsenic and selenium were measured in the feathers of adult brown pelicans and chicks in several breeding colonies (Shamrock Island, Chester Island, Marker 52 Island, North Deer Island, Raccoon Island, Felicity Island, Gaillard Island, Audubon Island, and Ten Palms Island) in the Northern Gulf of Mexico. Overall, most chicks and adults examined had mercury levels in feathers that were below the concentration range in which birds show symptoms of mercury toxicity. However, chicks in the Audubon Island and Ten Palms Island colonies displayed mercury levels that were 3 times higher than values observed in 5 other colonies. In addition, several adults and chicks displayed selenium concentrations that are above what is considered safe for birds. Cadmium quantities in feathers were below levels that trigger toxicity in birds. Similarly, arsenic measurements were at quantities below the average of what has been reported for birds living in contaminated sites. Finally, we identify pelican breeding colonies that may warrant monitoring due to elevated levels of contaminants.

Alabama, Florida, Louisiana,Texas↗
USGS2020

Nonlinear patterns in mercury bioaccumulation in American alligators are a function of predicted age

Mercury is a widespread, naturally occurring contaminant that biomagnifies in wetlands due to the methylation of this element by sulfate-reducing bacteria. Species that feed at the top trophic level within wetlands are predicted to have higher mercury loads compared to species feeding at lower trophic levels and are therefore often used for mercury biomonitoring. However, mechanisms for mercury bioaccumulation in sentinel species are often poorly understood, due to a lack of long-term studies or an inability to differentiate between confounding variables. We examined mercury bioaccumulation patterns in the whole blood of American alligators ( Alligator mississippiensis ) from a long-term mark-recapture study (1979–2017) in South Carolina, USA. Using a growth model and auxiliary information on predicted age at first capture, we differentiated between age- and size-related variation in mercury bioaccumulation, which are often confounded in alligators due to their determinate growth pattern. Contrary to predictions that the oldest or largest individuals were likely to have the highest mercury concentrations, our best-supported model indicated a peak in mercury concentration at 30–40 years of age, depending on the sex, and lower concentrations in the youngest and oldest animals. To evaluate the robustness of our findings, we re-analyzed data from a previously published study of mercury in alligators sampled at Merritt Island National Wildlife Refuge in Florida. Unlike the South Carolina data, the data from Florida contained minimal auxiliary information regarding age, yet the best supported model similarly indicated a peaked rather than increasing relationship between mercury and body size, a less-precise indicator of age. These findings highlight how long-term monitoring can differentiate between confounding variables (e.g., age and size) to better elucidate complex relationships between contaminant exposure and demographic factors in sentinel species.

Florida, South Carolina↗
USGS2019

Seasonal variation in environmental and behavioural drivers of annual-cycle habitat selection in a nearshore seabird

Aim Conservation of highly mobile species often requires identifying locations or time periods of elevated vulnerability. Since both extrinsic habitat conditions and intrinsic behavioural and energetic requirements contribute to habitat use at the landscape scale, identifying spatial or temporal foci for conservation intervention requires understanding how habitat needs and distributions vary across the annual cycle. Nearshore marine birds inhabit highly dynamic systems and have widely varying habitat needs among breeding, moult and non-breeding seasons, making them a useful case study for testing the relative contributions of individual resource requirements and environmental conditions in driving annual variation in distribution patterns. Location Northern Gulf of Mexico (USA). Methods We tracked Brown Pelicans using bird-borne GPS transmitters and used a combination of Hidden Markov Models and multivariate selectivity analysis to compare the characteristics of preferred resident habitats used throughout the annual cycle. Results Habitat selection was driven by dynamic oceanographic variables during all stages of the annual cycle. Key habitat characteristics varied between seasons, with particularly strong selection on high productivity, low temperature and low salinity during the breeding and post-breeding moult periods. The post-breeding moult also corresponded to a time of limited availability of preferred habitats, resulting in extensive overlap between breeding populations from different administrative planning areas. Main conclusions By incorporating seasonal variation in individual behaviour and resource requirements into our habitat models, we were able to identify the post-breeding moult as a period of high selectivity and restricted availability of preferred habitats for Brown Pelicans. Locations meeting preferred habitat criteria during the post-breeding period, particularly estuarine habitats with high productivity and low salinity, would therefore be high-value targets for management and restoration. Our analysis demonstrates the importance of accounting for both intrinsic and extrinsic temporal variation in evaluating habitat selection.

Alabama, Florida, Louisiana, Mississippi, Texas↗