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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.

The little-known Eurasian Sparrowhawk of Macaronesia (Accipiter nisus granti), also named as the Macaronesian sparrowhawk, is endemic to Madeira Island and the Canary Islands (North Atlantic Ocean) and has the smallest area of distribution of the sparrowhawk subspecies. We studied the breeding biology of the Macaronesian sparrowhawk for the first time on Madeira Island, Portugal. Specifically, we described nests, tree nests, nest sites, and nesting territories, and we estimated incubation, hatching and fledging dates. Moreover, we evaluated the influence of altitude on the date of the initiation of breeding and measured the number of fledglings and the factors influencing this parameter. Most nesting territories (88.6%) were located in forest patches where valleys with watercourses were present. Breeding success (73.2% ± 0.1 SE, n = 18) and the mean number of young fledged per nest with eggs (2.27 ± 0.04) are lower than the values for the Canary Islands. Altitude influenced the date of the initiation of breeding, with pairs in lowlands (<700 masl) initiating breeding earlier. However, pairs breeding earlier did not have higher reproductive rate than those breeding later. The number of fledglings per nest with eggs in mixed habitats was higher than in exotic and Laurel forests. The main cause of breeding failure was forest cutting. We believe that if the forestry industry does not consider the nesting areas, as well as the breeding phenology of this subspecies, and forest fires are not prevented, then its population in Madeira may be reduced in the near future., Nest