On the island of O‘ahu, Hawai‘i, USA, hundreds of the native seabird Wedge-tailed Shearwater Ardenna pacifica (WTSH) experience mortality from fallout every year. However, not all lights are created equal in their influence on seabird fallout. This study evaluated trends from standardized surveys that were conducted from 2002 to 2010 along a road with high colony density looking for WTSH fallout. Yearly fallout counts showed an oscillating two-year cycle of increasing and decreasing fallout and identified November 25th as the date with the highest fallout. Fallout individuals were found near artificial lights and utility lines at extremely high percentages; at 94% and 83% within 8 m, which was much higher than random points analyzed along the same route. Fallout was also negligible farther than 5 km from the nearest colony and occurred in a small area of the transect, where 60% of all fallout occurred along a 1.7 km section, with 27% of fallout occurring within 8 m of only two light poles, highlighting the high potential for targeted management. Outcomes of rescued shearwaters from non-fatal fallout events showed that 78% were admitted for rehabilitation with no injury and released suggesting that rescue efforts during high-risk periods that are focused within 5 km of colonies, in fallout hot spots, are likely to enhance survival in addition to light alteration at these sites. Our results specify when, where, and how targeted management could be used most effectively to reduce fallout on O‘ahu and highlight tangible and easily applicable solutions to artificial light-induced mortality on Hawaiian seabirds.
More info at: Friswold et al. 2020. Wedge-tailed Shearwater Ardenna pacifica fallout patterns inform targeted management. Marine Ornithology
The Manx shearwater Puffinus puffinus is one of the best studied seabirds worldwide. Most of the information known on this seabird is focused on the northern core populations where the species is abundant. However, the species shows a high number of peripheral populations, which are extremely small and difficult to study in comparison to central populations. Using an integrative approach, we provided evidence of phenological, morphological, acoustic, plumage colour, and genetic differentiation of the Canarian Manx shearwaters (the most southern population) from the northern breeding colonies, which is compatible with a long period of isolation. Birds from the Canary Islands breed around 2‐3 months earlier, are smaller and lighter, and show darker underwing plumage than those from northern populations. In addition, Canarian call features are different from the northern populations and genetic analyses of the mitochondrial control region indicate an incipient genetic differentiation of Canarian Manx shearwaters from the other breeding populations. The Canarian population holds a small number of breeding colonies and it is declining, so accurate taxonomic recognition critically affects conservation efforts. We propose to rank the Canarian breeding population as a new subspecies Puffinus puffinus canariensis ssp. nova.
More info at: Rodríguez et al. 2020 Cryptic differentiation in the Manx Shearwater hinders the identification of a new endemic subspecies. Journal of Avian Biology
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