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Monitoring Sea birds in Cabo Verde
Launched in 2017, our bird conservation programme is the first comprehensive field study on Sal’s resident and migratory bird species.
Birds, and especially seabirds, serve as important indicators of the health of the surrounding ecosystem. Our team collects critical nesting, feeding, and migration data on several key indicator species.
Rapid coastal development, overfishing, marine pollution and the introduction of domesticated species such as cats and dogs are placing increasing pressure on the habitats and feeding patterns.
Our bird monitoring team currently works with over seven species of birds on Sal Island to better understand their roles in the island’s ecosystem. Our collection and analysis of this data will provide an essential roadmap for developing future conservation strategies of these important birds.
Seabirds:
A Barometer for Biodiversity
Seabird populations, their breeding habits and their diets all offer important insight into the health of the surrounding marine ecosystem. As marine predators that are accessed with relative ease, the remains of their diet provides us with a fresh sample of their prey species, that can be simultaneously studied in real time.
Seabirds play important roles as:
Biological Indicators
Their health reflects the quality of their surrounding environment and any changes it undergoes over time.
A Source of Nitrogen
The nitrogen and potassium from their excrement (also known as guano) provide essential nutrients for soil and ocean cycles as well as for local plant vegetation.
Natural Ocean Samplers
By taking samples of their diet researchers are looking for the presence of organic and inorganic contaminants.
Seabirds at a Glance:
340 Species Globally
We can find up to 350 species of seabirds in the World. From them, 8 can be found in Cabo Verde and 5 in Sal Island.
Specialised Fishers
They have waterproof feathers that allow them to plunge-dive to catch fish and squid. Others, like penguins, use their wings like fins.
Drink Saltwater
They evolved with a sal processing gland that allows them to drink salt water. The excess of salt is excreted through the nostrils.
Colonies & Migration
Seabirds breed in aggregations or colonies that they leave to migrate to feeding areas with species rich in their diet.
Red-Billed Tropicbird
Scientific Name: Phaethon aethereus
Local Name: Rabo-de-junco
Habitat: Coastal cliffs, in rocky areas and cliffs. Nest inside holes.
Breeding season: Year-round breeding with a seasonal peak from December-April.
Migration: Middle of Atlantic Ocean, between CV and the north of South America.
Threats: Predation by humans, introduced animals (rats, cats, dogs), accidental catches by fisheries.
IUCN Status: Least Concern - Population trend: Decreasing
Endemic: Native to Cabo Verde
Wingspan: 95-106 cm
Diet: Squid, small fish
Red-billed Tropicbirds
Red-billed tropicbirds (Phaethon aethereus) are a loosely colonial species that nest in the rocky cliffs where there is easy access to the open sea. Their diet consists primarily of small fish and squid caught by plunge-diving.
It’s in part their breeding patterns that make Red-billed tropicbirds particularly sensitive to environmental changes.
This species often return to the same locations to breed and remain as a pair throughout their lifetime making them increasingly vulnerable to threats such as predation from introduced species such as cats, rats, and other mammals, as well as human-induced threats such as ocean pollution and poaching of adults and chicks.
Red-billed tropicbirds are nationally protected throughout Cabo Verde, though this particular population is still listed as endangered.
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In 2018, our team's data collection in the field led scientists from the University of Barcelona to identify Sal Island as likely the most important breeding site for red-billed tropicbird in West Africa.
Seabirds of Sal Island
In addition to the red-billed tropicbird, our team has recorded four other species of seabird currently nesting on Sal Island. Though these species share a number of the same general characteristics of seabirds, they each possess their own unique breeding and migratory patterns.
Cabo Verde Little Shearwater
Scientific name: Puffinus lherminieri boydi
Local Name: Pedreiro, Supletifogo
Breeding ground: on the coast, in rocky areas and cliffs and inside holes in sand and mud made by Pedreiro azul (Pelagodroma marina aedesorum).
Breeding season: February- May
Migration: between CV and the north of Brazil.
Threats: introduced animals (rats, cats), mortality associated with light pollution.
IUCN Status: Least Concern
Endemic: Endemic subspecies to Cabo Verde
Wingspan: 58-61 cm
Diet: small fish, squid, crustaceans
Cabo Verde Storm-petrel
Scientific name: Hydrobates jabejabe
Local Name: Pedreirinho
Breeding ground: on the coast, in rocky areas and cliffs. Nest inside holes
Breeding season: possibly in two different seasons, still under research
Migration: Unknown
Threats: introduced animals (rats, cats), mortality associated with light pollution
IUCN Status: Vulnerable
Endemic: Endemic to Cabo Verde
Wingspan: 43-46cm
Diet : Small fish
Cabo Verde Shearwater
Scientific name: Calonectris edwardsii
Local Name: Cagarra
Breeding ground: on the coast, in rocky areas and cliffs. Nest inside holes
Breeding season: June- November
Migration: south of Brazil and Uruguay.
Threats: predation by humans, introduced animals (rats, cats), accidental catches by fisheries :
IUCN Status: Near Threatened
Endemic: Endemic to Cabo Verde
Wingspan: 101-112 cm
Diet: mall fish, squid
Bulwer’s petrel
Scientific name: Bulweria bulwerii
Local Name: João Preto
Breeding ground: on the coast, in rocky areas and cliffs. Nest inside holes
Breeding season: June- September
Migration: Middle of the Atlantic Ocean, between West Africa and the north of Brazil
Threats: Introduced animals accidental catches by fisheries and mortality associated with light pollution.
IUCN Status: Least Concern
Wingspan: 63-73 cm
Diet : small fish, squid, crustaceans, plankton
Other Birds:
Osprey
Scientific name: Pandion haliaetus
Local Name: Guincho
Habitat: Close to bodies of water. Elevated nests
Breeding season: December- April
Migration: Resident in Cabo Verde, few migrate to neighbouring islands
Threats: Illegal capture , introduced animals, human activities deterring breeding, pollution
IUCN Status: Least Concern
Endemic: Native to Cabo Verde
Wingspan: 127-180cm
Diet: Fish
Ospreys (Pandion haliaetus) is a resident species in Cabo Verde. They are a bird of prey found across the globe. Preferring high nesting areas out of reach of predators, you can find them nesting in Sal from cliffs, mountain-tops, tree-tops to tall abandoned human structures. The nests are often made out of sticks and often include various types of marine debris, where especially parts of fishing nets can be fatal to chicks. This species might hunt for the occasional rodent; however, their diet consists of 99% of fish.
They prefer hunting in the calmer, shallow waters around the island or in freshwater, with impressive diving skills their catch measures on average 15-30cm. The population of resident ospreys in Cabo Verde is more abundant in the northern islands than in the southern ones, where this species is scarcer. In the past, their numbers have been greatly reduced by overharvesting of eggs and nestlings. Predation has been reducing recently but is still one of the main threats to their population on Sal Island. Ospreys are particularly sensitive to human activities, where disturbances including tourism-related activities result breeding failures. They are usually a monogamous species,
Threats to Birds
Sadly, humans are responsible for 99% of species extinction in the world. Recent studies found that the current extinction rate is between 1,000 and 10,000 times higher than the “normal” extinction rate (background rate). While before, only 0,1 species from every million went extinct yearly, now this number is at least 100 in every million species.
Tools For Conservation
Until recently, little was known about the health and conservation status of the seabird species on Sal.
As an indicator species, seabirds can assist in piecing together important information about the health of the surrounding ecosystem and environment. In partnership with the University of Barcelona's Seabird Ecology group, we are working on collecting specific data that will provide critical information on the health of Sal's seabird populations, and by extension, the surrounding ecosystem.
Here are a few ways we are monitoring and conserving various bird species on Sal:
Mitigation tools – Invasive species
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Monitoring and population management of invasive species
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Awareness raising on the impact of invasive species such as cats and dogs from nearby settlements
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Sterilisation and castration campaigns to reduce the population of invasive species such as cats and dogs
Community outreach
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Partnering with community associations such as Guardians of the Sea to minimise bycatch of seabirds, voluntary beach patrols and more;
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Tools (scary birds) and techniques (safe release techniques for seabirds) for the fisherman to reduce the impact of artisanal fisheries in seabirds;
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Seabird exhibition increasing awareness with local and international communities
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Promotion of environmental education in schools and children centres;
Census
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Regular census of the nesting bird species to assess populations
Scientific Research
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Collection of biometric data to research population trends such as uropygial fat to help identify organic and inorganic contaminants, blood extraction to determine diet and migratory pattern and feathers for DNA analysis and determining the sex
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Ringing birds for population study - tracking the size of the population here on Sal, as well as learn more about the age and duration of sexual maturity
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Control the weight and measurements of both adults and chicks to know the food supply status - less weight gain could mean a depletion of fish stocks.
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Placement of geolocators to determine migration patterns and areas of travel after their breeding season;.
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Placement of GPS devices to determine feeding areas during the incubation and the rearing periods and the differences between incubation and breeding periods
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Placement of GPS devices on boats that determinate human-seabirds conflict.
Volunteer with us!
If you are looking to kick-start your career in ornithology and develop new skills, our island conservation volunteering programme is for you! Gain hands-on field experience working with locally and globally iconic species. We're only taking a limited number of volunteers at a time and are looking for people ready to make a meaningful contribution and who are prepared for some challenging, but very fulfilling work.
Main Project Partners
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