Figure - uploaded by Fernando Medrano Martínez
Content may be subject to copyright.
Summary of the captures and recaptures made for (a) chicks, captured as prospectors in subsequent years; (b) breeders and (c) birds captured through mist-netting.
Source publication
Phenological divergence between conspecific populations breeding sympatrically is increasingly recognized as an important evolutionary process that may lead to allochronic speciation. However, the extent to which adaptation to differences in the timing of breeding may contribute to this process remains unclear. In this study, we assessed breeding p...
Contexts in source publication
Context 1
... the birds initially captured in the hot season, one was subsequently recaptured in the hot season and 8 in the intermediate period. Ringing and recapture data are summarized in Table 1. ...Context 2
... bottom of the diagram shows the percentage of individuals that were initially captured in each season while the top shows the percentage of individuals during the period when they were recaptured for (A) birds ringed as chicks; (B) birds ringed as breeding adults and; (C) birds ringed in mist-nets. Sample sizes are summarized in Table 1. appeared to be higher than that within years between populations. Duration of the non-breeding period (x ̄ : 168.8 days; range: 7.0-266.5 ...Similar publications
Background
Ecological segregation allows populations to reduce competition and coexist in sympatry. Using as model organisms two closely related gadfly petrels endemic to the Madeira archipelago and breeding with a two month allochrony, we investigated how movement and foraging preferences shape ecological segregation in sympatric species. We teste...
Citations
... A key question in this regard is whether the reproductive isolation associated with the divergence in the timing of breeding is the exclusive driving force leading to speciation or if this phenomenon is further enhanced by additional mechanisms, such as ecological differentiation through local adaptation to seasonal conditions (Dieckmann et al. 2004, Taylor & Friesen 2017. So far, the evidence shows that populations that have already undergone speciation exhibit greater levels of ecological divergence than those still in the process of speciation (Medrano et al. 2022, Wang et al. 2022). However, this evidence remains limited, especially concerning migratory patterns and non-breeding distribution, Therefore, it is important to expand the scope of research by conducting more studies involving a wider range of taxa. ...
... Also, we found that the activity patterns of both species were influenced by the moon's illumination at night, with the birds spending more time on the water on darker nights. These patterns have also been documented for some other storm-petrel species, such as the white-faced storm-petrel Pelagodroma marina (Medrano et al. 2024), but not for other storm-petrel species, such as the European storm-petrel Hydrobates pelagicus or the Cape Verde storm-petrel H. jabejabe (Medrano et al. 2022. ...
... Ecological divergence between allochronic populations that al ready speciated has been previously reported for some physiological traits, like proteins that are re lated with thermoregulation (Wang et al. 2022). Conversely, allo chronic populations breeding in tropical systems did not show such a divergence in their space utilization during the non-breeding period (Medrano et al. 2022). This lack of spatial separation may facilitate connectivity and inhibit speciation from occurring. ...
Migration is an essential life stage in many species, but is little understood in some groups, e.g. storm-petrels. Considering that storm-petrels reside in non-breeding areas for over half of their lifespan, identifying these areas is a priority for conservation efforts. Townsend’s Hydrobates socorroensis and Ainley’s storm-petrels H. cheimomnestes are 2 threatened sister species, breeding allochronically on Guadalupe Island (Mexican Pacific), for which migratory patterns are unknown. In this article, we describe the non-breeding areas of these 2 species, assess artificial light events recorded by geolocators, and describe the birds’ daily activity patterns. We deployed geolocators from 2021 to 2023 and modeled migratory routes using SGAT. We successfully tracked 7 Townsend’s and 4 Ainley’s storm-petrels over their non-breeding period. Townsend’s storm-petrels were found to travel to the south of the Baja California Peninsula and spent most of the time in Mexican waters, while Ainley’s storm-petrels migrated toward Hawaii and spent most of the time on the high seas. For the Townsend’s storm-petrels, 16.1% of their core areas are in protected waters, whereas for Ainley’s storm-petrel, only 0.7% of the core areas are protected, and 0.8% of those areas are recognized as key biodiversity areas (KBAs). Further, our findings indicate that both species are mainly nocturnal, making them highly susceptible to the impacts of light pollution; we detected 6 artificial light events. Our findings also support the hypothesis that divergence in the migration patterns between allochronic populations could be a crucial factor in sympatric speciation, which seems likely in seasonal environments like the northern Pacific.
... Cabo Verde, consists of 10 volcanic islands that lie between 600 and 850 km west of Senegal, Africa (Figure 1a,c), located at the eastern boundary of the North Atlantic subtropical gyre at the southern limit of the Canary Current (Fernandes et al., 2005). The waters around St Helena are characterised by a generally low chlorophyll a concentration with substantial variation in spatial distribution between years (maximum range 0.3-0.5 mg/m 3 ) (Thorpe et al., 2020), whereas Cabo Verde is considered a more productive oceanic region with more enriched waters (chlorophyll a concentration range 0.06-4.1 mg/m 3 (Medrano et al., 2022;Silva, 2022;Vieira, 2019)). ...
Body condition in pelagic seabirds impacts key fitness‐related traits such as reproductive performance and breeding frequency. Regulation of body condition can be especially important for species with long incubation periods and long individual incubation shifts between foraging trips. Here, we show that body condition of adult Red‐billed Tropicbirds ( Phaethon aethereus ) at St Helena Island, South Atlantic Ocean, exhibited considerable variation between years (2013–2017) and between different stages of the breeding cycle. Females took the first incubation shift following egg laying, after which males and females alternated incubation shifts of varying length, ranging from <1 to 12 days. Body condition declined in both sexes during an incubation shift by an average of 22 g (2.83% of starting mass) per day and over the incubation period; mass loss was significantly greater during longer incubation shifts, later within a shift and later in the total incubation period. There was also significant differences in incubation behaviour and body condition between years; in 2015, coinciding with a moderate coastal warming event along the Angolan‐Namibian coastlines, adults on average undertook longer incubation shifts than in other years and had lower body condition. This suggests that substantial between‐year prey fluctuations in the Angola Benguela upwelling system may influence prey availability, in turn affecting incubation behaviour and regulation of body condition. Adults rearing chicks showed a significant reduction in body condition when chicks showed the fastest rate of growth. Chick growth rates during 2017 from two localities in the Atlantic Ocean: an oceanic (St Helena) versus neritic (Cabo Verde) population were similar, but chicks from St Helena were overall heavier and larger at fledging. Results from this multi‐year study highlight that flexibility and adaptability in body condition regulation will be important for populations of threatened species to optimise resources as global climate change increasingly influences prey availability.
... geolocators were attached to a metallic ring on the tibia using stainless steel wire (Supplementary Electronic Material, Figure 2). These devices have been used to study individuals of similar-weight species in the north Atlantic and Pacific, such as leach's Storm-petrel Hydrobates leucorhous (Pollet et al., 2014(Pollet et al., , 2019 and the Cape Verde Stormpetrel H. jabejabe (Medrano et al., 2022) without causing detrimental effects. ...
... We analysed changes in the daily proportion of time spent on the water, based on wetdry data collected in the geolocators, under the assumption that it is an indicator of resting sessions (e.g., Militão et al., 2022;Medrano et al., 2022) during the non-breeding period. Two of the six tracks from the geolocators had incomplete wet-dry data (due to memory issues) and were excluded from the activity patterns analysis. ...
... This pattern is well-documented for seabirds, such as gadfly petrels (Pastor-Prieto et al., 2019) and little shearwaters (Ramos et al., 2020). however, previous studies on Storm-petrels of the family hydrobatidae have shown a weak relationship between activity and moon brightness (e.g., Militão et al., 2022;Medrano et al., 2022). Further research is needed to understand if the foraging behaviour of the hydrobatidae and Oceanitidae stormpetrels families usually differ, which may reflect trophic differences. ...
Seabirds spend most of the year offshore, out of human sight, covering great distances while migrating and foraging for food often in remote areas of the high seas. Several small seabirds that anthropogenic activities might threaten have hitherto remained untracked. One such species is the anti-tropical White-faced Storm-petrel Pelagodroma marina. Indeed, its movements and activity patterns are largely unknown, although often regarded as dispersive. In this study, we aimed to identify the post-breeding movements and the daily activity patterns of White-faced Storm-petrels breeding in Cabo Verde (P. m. eadesorum). We tracked five adults with geolocators (glS) between 2019 and 2022 and modelled their routes using Satellite geolocation for Animal Tracking (SgAT). We programmed geolocators to record when the bird was dry or on the water to understand their daily activity patterns during the non-breeding period. Results showed that the White-faced Storm-petrels breeding in Cabo Verde are truly migratory, heading towards the northwest Atlantic in May-June and returning in October-november through the northeast towards Cabo Verde, following a clockwise movement. Birds spent the non-breeding period in areas associated with seamounts along the mid-Atlantic Ridge and south of the Azores. In addition, we found that the species is mainly active at night during the non-breeding season, suggesting that it takes advantage of the diel vertical migration of zooplankton and nekton associated with seamounts. The time spent on the water increased before returning to the colony, probably due to reduced flying ability during the moulting period. Our data add to the growing evidence that the north-central Atlantic is a crucial location for the conservation of pelagic seabirds and highlights the need to protect these remote areas from the increasing human impact on the high
... We used tracks from 7 black-capped petrels captured at sea to further enhance our understanding of the spatial distribution of the species in the western North Atlantic. Color forms appeared to differ in their non-breeding distributions and hence their macroscale exposure to marine threats, potentially leading to phenotypically specific ecological niches and differential ex posure to ecological drivers of pheno typic divergence (Medrano et al. 2022). ...
... Differences in the marine distribution between age groups and/or breeding status may occur within species of pelagic seabirds and therefore could contribute to the dual distribution we observed in our study (e.g. a confounding effect of age or breeding status) (Medrano et al. 2022). For example, juveniles, immatures, and adults may have different spatial or temporal distributions (Péron & Grémillet 2013, Frankish et al. 2020, and failed breeders may have similar or different distributions compared to nonbreeders , Bogdanova et al. 2011. ...
Despite growing support for ecosystem-based approaches, conservation is mostly implemented at the species level. However, genetic differentiation exists within this taxonomic level, putting genetically distinct populations at risk of local extinction. In the diablotin black-capped petrel Pterodroma hasitata , an endangered gadfly petrel endemic to the Caribbean, 2 phenotypes have been described: a smaller dark form and a heavier light form, which are genetically distinct. To assess possible differences in the marine distributions of phenotypes, in May 2019, we captured 5 adult black-capped petrels of each phenotype at sea in the western North Atlantic and equipped them with satellite transmitters. We used generalized linear mixed models to test the importance of phenotype on geographic distribution. Using kernel density estimations, we located use areas, quantified spatial overlap between forms, and assessed form-specific exposure to marine threats. Petrels were tracked for 11 to 255 d ( mean ± SD: 102.1 ± 74.2 d). During the non-breeding period, all individuals ranged from 28.4 to 43.0° latitude. Phenotypes had significantly distinct non-breeding distributions, independent of time of year. The dark form used waters of the Carolinian marine ecoregion, and the light form used pelagic waters of the Virginian ecoregion, to the north. The dark form was more exposed to marine threats than the light form, in particular to mercury, microplastics, and marine traffic. The light form overlapped with proposed wind energy areas off the central US coast. These differences in exposure suggest possible differences in vulnerability, which can have repercussions on the viability of this imperiled species.
... We used tracks from 7 black-capped petrels captured at sea to further enhance our understanding of the spatial distribution of the species in the western North Atlantic. Color forms appeared to differ in their non-breeding distributions and hence their macroscale exposure to marine threats, potentially leading to phenotypically specific ecological niches and differential ex posure to ecological drivers of pheno typic divergence (Medrano et al. 2022). ...
... Differences in the marine distribution between age groups and/or breeding status may occur within species of pelagic seabirds and therefore could contribute to the dual distribution we observed in our study (e.g. a confounding effect of age or breeding status) (Medrano et al. 2022). For example, juveniles, immatures, and adults may have different spatial or temporal distributions (Péron & Grémillet 2013, Frankish et al. 2020, and failed breeders may have similar or different distributions compared to nonbreeders , Bogdanova et al. 2011. ...
Aim
Despite growing support for ecosystem-based approaches, conservation is mostly implemented at the species level. However, genetic differentiation exists within this taxonomic level, putting genetically distinct populations at risk of local extinction. In seabirds, reproductive isolation is one of the principal drivers of genetic structure. In the Diablotin Black-capped Petrel Pterodroma hasitata , an endangered gadfly petrel endemic to the Caribbean, two phenotypes have been described: a smaller dark form and a heavier light form, which are genetically distinct. We hypothesized that color forms have a similar non-breeding distribution at sea but distinct nesting distributions.
Location
Western North Atlantic and northern Caribbean islands.
Methods
In May 2019, we captured 5 adult Black-capped Petrels of each phenotype at sea and equipped them with satellite transmitters. We used generalized linear mixed models to test the importance of phenotype on geographic distribution. Using kernel density estimations, we located use areas, quantified spatial overlap between forms, and assessed form-specific exposure to marine threats. Finally, we used tracking data to estimate the distribution and timing of nesting.
Results
Petrels were tracked for . During the non-breeding period, all individuals ranged from 28.4 – 43.0 degrees latitude. Phenotypes had significantly distinct non-breeding distributions. In the western North Atlantic, the dark form was exposed to more marine threats than the light form. We recorded two trips (1 individual of each form) to known breeding areas, with the light form initiating breeding 1.5 months before the dark form.
Main conclusions
Phenotypic differences in the Black-capped Petrel were linked to differences in nesting phenology, non-breeding marine distribution, and at-sea threat exposure. To sustain the species’ representation, redundancy, and resiliency in the light of environmental changes, it is likely that the evolutionary processes that resulted in genetic differentiation will also need to be conserved.
