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:

Seabirds at a Glance:

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.​

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-bill 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. 

Threats to Seabirds

Osprey

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 measuring the health of seabird species on Sal: 

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Sampling of adults

• Uropygial fat to help identify organic and inorganic contaminants;

• Blood extraction to determine the sex of the animal;

• Feathers: to collect information on the diet of the local population.

Movement tracking​

• Placement of geolocators to determine migration patterns and areas of travel after their breeding season;​

• Placement of GPS devices to determine feeding areas during the incubation and the rearing periods and the differences between incubation and breeding periods;

• Placement of GPS devices on boats: determinate human-seabirds conflict.

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Ringing and biometrics

• Support population study - tracking the size of the population here on Sal, as well as learn more about the age and duration of sexual maturity;

• 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.

Other Monitoring Initiatives

Main project partners: