Annual Lifecycle of a Seabird – autumn adventures
Juvenile wanderers start to explore their future home while seasoned adults take off to familiar routes.
Youngsters – vagabonds off to find a home in the rough sea
As the days get shorter, seabird colonies become less busy. As the adults depart to reach their wintering grounds, the juveniles fledge and test their wings with the first flapping. After a few attempts, the young birds leave their homes, adventuring for the first time into an unknown world that will soon be their home – the ocean. Juveniles and immature birds are usually more exploratory than adults. The post-breeding migration in autumn is likely to present variations in routes, timing, and behaviour between juvenile, immature, and adult birds.
Data on Scopoli’s shearwater Calonectris diomedea breeding on two French Mediterranean islands revealed remarkable age-related differences. Juveniles spent more time in the Balearic Sea, showed lower synchrony in crossing the Gibraltar strait, had more sinuous pathways and covered longer daily distances compared to immatures and adults. Younger birds may have limited navigational skills and progressively learn detailed migration routes, allowing them to find better traveling paths and wintering areas. Yelkouan shearwaters Puffinus yelkouan juveniles tracked from Northeast Malta traveled towards the southern coasts of the Mediterranean and reached Libya and Egypt. These regions are relatively poor in food resources. In contrast, the tagged adults from the same colonies headed to the Gulf of Gabes, a nutrient-rich area.
Marine Flyways: blue highways across the planet
No matter what age, seabirds travel vast distances across the seas. Migration routes can vary among different populations and depending on sex and environmental changes, which all can influence migratory behavior. Birds adapt migration schedules and routes year by year in response to direct or indirect effects of heterogeneity in the environment.
Many seabird species undertake incredible migrations traveling from pole to pole or circumnavigating the globe. Using a vast amount of tracking data from long-distance migratory seabirds, BirdLife International has identified six global Marine Flyways., They highlight the connectivity at an ocean basin level and the need for coordinated action to address seabird declines and enhance conservation efforts.
The Atlantic Ocean Flyway is used by many species breeding in Europe, including BirdLife’s symbol, the Arctic Tern Sterna paradisaea, which performs the longest migration known in the animal kingdom. Cory’s Shearwaters Calonectris borealis also use this flyway during their migration journey – they follow an 8-shape pattern with frequent stopovers around West African coasts and the Southwestern coasts of Ireland and Great Britain.
This species exhibits migratory flexibility between years, meaning they do not have a set destination during their migration across the Atlantic Ocean. Age and experience progressively influence the refinement of migratory behaviour and year-round spatial distribution.
Threats: an ever increasing glaring world
Not all the youngsters head straight to the sea; some fall victim to light pollution from coastal developments (including lamps, cars and buildings) or from cruises. They can often be found stranded on land, which increases the chance of predation by dogs and cats or being struck by vehicles. For the last decade, some of our BirdLife Partners in the region have been involved in reducing and mitigating the impacts of light pollution on seabirds, an emerging threat that causes fatalities around the globe.
In the idyllic Macaronesia archipelagos of Canary, Madeira and Azores, more than 1000 seabirdsdie each year due to light pollution. Our Partners in Portugal (SPEA) and Spain (SEO/BirdLife), under the LIFE Natura@night project (https://naturaatnight.spea.pt/en) are achieving promising results within the Macaronesia region. Their efforts include collaboration with municipalities to adopt Lighting Master Plans and installing adjustable lights that can regulate intensity and temperature., These measures help to minimize negative effects on the local seabird population, enhance safety, energy savings, and lower ecological impact.
Below you can find a video on the issue that was published by our Portuguese Partner:
Para as aves marinhas, as viagens noturnas tornaram-se numa batalha pela sobrevivência devido ao encandeamento causado pelas luzes artificiais. ⚠️💡
— SPEA (@spea_birdlife) November 15, 2023
Na Macaronésia a poluição luminosa mata mais de 1000 aves marinhas por ano. 🐦
➡️ https://t.co/NfPrNl8FZB#LIFENAturaatnight pic.twitter.com/gghqR3RoJZ
Our Partner in Cabo Verde (Bisofera) has also been implementing a successful awareness and education campaign aimed at the general public (Campanha SOS Edu), which contributed to rescuing many stranded birds so far, as you can see in their below Social Media post from December 2023:
The impact of light pollution on seabirds has also been addressed by our Maltese Partner, BirdLife Malta. Their TV series, called NATURAlment, is broadcasted weekly through a local TV channel and focuses on the natural environment of the Maltese Islands. They also showcase what the organization has done to address and mitigate the effects of light pollution. Additionally, BirdLife Malta has produced GUIDELINES FOR ECOLOGICALLY RESPONSIBLE LIGHTING, to inform and advise on protecting the nocturnal environment for seabirds and beyond.
Article written by Antonio Vulcano
Cover Picture by ©Jackal Photography, shutterstock
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