Light-induced mortality of seabirds is a poorly understood phenomenon, largely because of the challenge to track seabirds at night from their nests to the grounding light-polluted locations. New tracking technologies can inform about this phenomenon. Here, we used GPS transmitters with remote download to track the flights of Cory’s shearwater Calonectris borealis fledglings from an inland experimental releasing site to the ocean. We released birds assigned to three experimental groups: GPS tagged, tape-labelled, and control birds. We assessed how both intrinsic (such as body mass, body condition, body size, and down abundance) and extrinsic (i.e., flight descriptors, such as distance, straightness, and flight duration, wind speed, or moon luminance) factors influenced light-induced groundings by using two datasets: one including the three groups and another including just the GPS tagged birds (as GPS devices provide unique information). GPSs with remote data download provided information on birds reaching the ocean, this being a substantial improvement to previous studies requiring recapture of the individuals to retrieve the data. GPS tracks of birds reaching the ocean allowed us to know that some birds overflew coastal urban areas so light-polluted as the landing sites of grounded birds. We provide novel scientific-based information to manage seabird mortality induced by artificial lights.
More info at: Rodríguez A, et al. 2022. Tracking flights to investigate seabird mortality induced by artificial lights. Frontiers in Ecology and Evolution
On O’ahu, Hawai‘i, fledgling wedge-tailed shearwaters leaving their nests for the first time are often disoriented by lights and may become grounded due to exhaustion or collision, exposing them to additional threats from road traffic and predation. Highway streetlights on O’ahu were changed from unshielded high-pressure sodium (HPS) to full-cutoff light-emitting diode (LED) streetlights in 2016. We conducted road surveys to locate road-killed shearwaters from 2012-2019 and compared mortality before and after the change in lighting. We also accounted for three potential environmental drivers of interannual variability in fallout: moon illumination, wind speed, and wind direction. While the effects of these environmental drivers varied across years, the interaction between moon illumination and wind speed was the most important predictor, suggesting that mortality related to fallout increases during nights with low moon illumination and strong winds. We did not find the change in streetlights to significantly affect the number of road-killed shearwaters observed in our surveys. However, due to potential species-specific disparities in the behavior and light attraction of petrels, similar studies are needed before energy saving LED lights are implemented throughout the Hawaiian archipelago.
More info at: Urmston et al. 2022. Quantifying wedge-tailed shearwater (Ardenna pacifica) fallout after changes in highway lighting on Southeast Oʻahu, Hawaiʻi. Plos One
The SOS Cagarro campaign aims to engage people and organizations in the rescue of Cory’s Shearwater fledglings disoriented by artificial lights in Azores. Using the data collected on Faial Island during the rescue campaigns from fifteen years (2005–2019), a new study examines the variations in body mass and body condition with respect to rescue date (a proxy of fledging date) and surface oceanic conditions using satellite imagery data. The results showed that late fledglings were in poorer body condition than early ones. Inter-annual variations in fledging body condition were observed but they were not related to surface oceanic conditions fluctuations. However, annual mean fledgling body condition was positively correlated with sea surface temperatures measured in the autumn of the previous year in a northern feeding area used by adults throughout the breeding season. This research can be useful to improve the management and success of the SOS Cagarro campaign, but also that of other rescue campaigns of seabird fledglings. Because body mass is especially important to their survival at sea as higher energy reserves give them more time to learn to feed efficiently, new actions or protocols can be developed in the rescue program. For example, when resources are limited, i.e., few volunteers and massive fallout, the rescue effort might focus on the birds with the greatest chance of survival, i.e., the fattest birds with more energy reserves.
More info at: Cuesta-García et al. 2022. Targeting efforts in rescue programmes mitigating light-induced seabird mortality: First the fat, then the skinny. Journal for Nature Conservation
Like other Procellariiformes, fledgling Manx shearwaters are affected by light pollution during their first flights. They come to the light, are somehow confused, and they land on the ground. While much research has been focused on understanding this phenomenon, only a few papers have been dedicated to explore how shearwaters are affected by light at a later stage of life. This study used a thermal imaging camera to record flying Manx shearwaters in a dense breeding colony. We used a small torch covered with different colours and intensity-blocking filters to investigate the effect of light on adult seabirds. Once all the videos were recorded, we used supervised machine learning to count the number of birds in different treatments. The results showed that adult Manx shearwaters avoided light stimulus at heir colony, and this avoidance depended on the light intensity, colour and duration. We counted less birds when we turned on strong intensity white light compared to the dimmed white. A similar intensity of blue, green and white light resulted in a similar avoidance in Manx shearwaters. But when we turned on a red light of similar intensity, we did not see any effect, suggesting that birds did not avoid our red light. Finally, longer duration of light-on interval results in a lower number of counted birds. These results suggest that turning on the light at a colony of shearwaters should be limited to a minimum. If the light is necessary, a low intensity and short duration of light, as well as light with more red components, should be preferred. Lastly, further research that investigates animals that might avoid light should be undertaken, since it is a phenomenon that is much harder to detect than attraction where animals congregate near light.
More info at: Syposz et al. 2021. Avoidance of different durations, colours and intensities of artificial light by adult Manx shearwaters. Scientific Reports.
Although most concern around the impacts of light pollution on breeding seabirds centres on lights on land, vessels at sea can also affect large numbers of seabirds that visit their colonies at night. In the 1980s, vessels fishing for rock lobsters around Tristan da Cunha killed hundreds of petrels each year when they were attracted to the ships' lights at night. Subsequent measures to reduce deck lighting to a minimum, and to cover all windows and portholes at night, have greatly reduced mortality in this fishery, but small numbers of petrels are still killed each year. Over the last eight years, petrels have been reported coming aboard fishing vessels on 13% of nights. These ‘night strikes’ are more common at the start of the breeding season in early summer and especially in autumn, when most petrel chicks leave the breeding islands. Night strikes can also occur at sea in the Southern Ocean well away from breeding islands. We recommend that all vessels operating in these waters should be required to black out all but the most essential lights, especially on dark nights, and when operating close to breeding islands.
More info at: Ryan PG, Ryan EM, Glass JM, 2021. Dazzled by the light: the impact of light pollution from ships on seabirds at Tristan da Cunha. Ostrich
Every year, hundreds of recently fledged Atlantic Puffins Fratercula arctica are found stranded in communities and industrial sites bordering colonies in the Witless Bay Seabird Ecological Reserve (WBSER), located in Newfoundland and Labrador, Canada, which hosts ~ 300,000 pairs. Coordinated efforts involving volunteers occur nightly during the puffin’s fledging season (August - early September) to rescue stranded birds and return them back to the ocean. In addition to saving lives and raising awareness on the impacts of light pollution, the Puffin and Petrel Patrol (PPP) also provides the opportunity to collect information on environmental conditions leading to strandings and on the health of the local breeding puffin population. Between 2011 and 2020, 3845 puffins were found during nightly searches, with the fewest birds found around the full moon. Years in which the highest number of stranded birds were found were the same years in which puffins weighed the most. These results suggest that information collected through the PPP can be used to monitor in a non-intrusive way the health of the local breeding population. This study also examined what proportion of puffins fledging from the breeding colonies in the WBSER are found stranded and was estimated at < 0.2%. Although > 300,000 of pairs of Leach’s Storm-Petrels Oceanodroma leucorhoa also breed in the WBSER, this species was rarely found in bordering communities. Rather, stranded birds were observed along the coast of Conception Bay, at minimal distances of 25 km inland from the WBSER. Stranding events during the species’ fledging period (September – November) were observed at industrial sites and associated with lower moon visibility and nights with northerly winds, suggesting that recently fledged storm-petrels originated from the Baccalieu Island Seabird Ecological Reserve, which hosts the largest colony in the world. This study highlights the need for stronger mitigative measures to minimize light emittance along coastlines bordering important breeding colonies with emphasis on industrial sites.
More info at: Wilhelm et al. 2021. Effects of land-based light pollution on two species of burrow-nesting seabirds in Newfoundland and Labrador, Canada. Avian Conservation and Ecology.
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
Seabirds are impacted by coastal light pollution, where they are attracted to and disoriented by artificial light at night, often leading to massive mortality events. While adults are occasionally recorded in fallout throughout the year, this phenomenon is most severe during
fledging season and juveniles comprise the majority of affected individuals. In a newly published perspectives article in Conservation Science and Practice, we explore a connection between the visual system development of burrow nesting seabirds and the observed higher vulnerability to light pollution by seabird juveniles. Undeveloped and untrained vision at fledging, together with behavioural inexperience, could explain differences observed between age groups. Multidisciplinary research is needed to clarify such effects further mitigate light induced mortality.
More info at: Atchoi E, Mitkus M, Rodríguez A (2020) Is seabird light‐induced mortality explained by the visual system development? Conservation Science and Practice e195.
In that section, the most relevant news about the project and other news related to seabird conservation will be highlighted