Blue-footed boobies are a fascinating species of seabird known for their bright blue feet. But just how many of these iconic birds are there in the world? In this article, we’ll explore the global population size of blue-footed boobies and look at how their numbers are faring over time.
What species is the blue-footed booby?
The blue-footed booby is the common name for a species of seabird scientifically known as Sula nebouxii. It belongs to the genus Sula in the family Sulidae. There are six species of boobies in this genus, but the blue-footed booby is the most widespread and well known.
Blue-footed boobies are large seabirds with long pointed wings and short fan-shaped tails. As their name suggests, adults have bright turquoise-blue feet. They have white undersides, brown bodies, and pointed greyish-blue bills. Males and females look alike. Juveniles have greyish-brown feet which gradually turn blue as they mature over 2-3 years.
Blue-footed boobies are found along the Pacific coasts of South and Central America from Peru up through California and Mexico. They breed colonially on offshore islands and feed by plunge diving into the ocean to catch fish.
What is their global population?
Estimating the total global population of blue-footed boobies is challenging. Their breeding colonies can fluctuate in size from year to year, and many colonies exist on remote offshore islands that aren’t regularly surveyed.
According to the IUCN Red List, the best available estimate for the global population is around 200,000 mature individuals. However, this estimate was made back in 2016 and is considered uncertain. Some experts believe the total population could be higher, possibly over 1 million birds.
Population estimates by region
More precise population estimates are available for some specific regions:
- Mexico: Approximately 14,500-24,500 breeding pairs, so 29,000-49,000 mature individuals
- Galapagos Islands (Ecuador): 84,000-117,000 mature individuals
- Gulf of California (Mexico): 25,000-100,000 mature individuals
- Peru: Over 54,000 mature individuals
Adding up these regional totals gives a minimum global population of around 192,000 mature blue-footed boobies. But many more likely exist in unsurveyed areas across their Pacific range.
Is their population increasing or decreasing?
The global population trend for blue-footed boobies is unclear. In some regions, populations appear to be stable or even increasing. But in other areas they are believed to be decreasing.
For example, populations have grown substantially in the Galapagos since the 1970s after they were no longer hunted for food by humans. However, their numbers have declined in the Gulf of California over the last 20 years due to factors like overfishing, climate change, and disturbance of nesting habitats.
On balance, the IUCN currently lists the blue-footed booby as a species of “Least Concern”. But they note more population monitoring is needed, especially in Peru and the Galapagos where a large portion of the global population resides.
Threats to blue-footed boobies
Some of the major threats believed to be impacting blue-footed booby populations include:
- Reduced prey availability from overfishing
- Disturbance of breeding colonies by humans
- Predation by invasive species like rats, cats, and dogs
- Ocean pollution such as oil spills and plastic
- Climate change affecting sea temperatures and fish distributions
Protecting key breeding colonies and limiting fisheries impacts will be important for the future survival of blue-footed booby populations.
Comparison to other booby species
Blue-footed boobies have a widespread range compared to most other booby species. Here’s how their population compares:
Species | Population | Population Trend |
---|---|---|
Blue-footed booby | ~200,000 | Uncertain |
Red-footed booby | 650,000-800,000 | Decreasing |
Masked booby | 500,000-1 million | Decreasing |
Brown booby | 200,000-500,000 | Decreasing |
Peruvian booby | 11,000-33,500 pairs | Decreasing |
The blue-footed booby is one of the most abundant booby species. The red-footed booby likely has the largest global population, but it is declining due to threats like habitat loss and harvesting for food. The masked booby is the next most populous, followed by the widespread brown booby.
In contrast, the Peruvian booby has a much smaller population limited to just a few breeding islands off Peru. Their restricted breeding range makes them more vulnerable to extinction.
With their relatively large and widespread population, blue-footed boobies remain one of the most resilient booby species. But continued monitoring and conservation will be needed to ensure their numbers remain stable into the future.
Conclusion
Blue-footed boobies are iconic seabirds known for their bright blue feet. While their exact global population is uncertain, the best estimate is around 200,000 mature individuals. However, the true number is likely higher based on regional totals and unsurveyed areas.
Some populations appear to be increasing, like in the Galapagos Islands. But others are decreasing due threats like overfishing, habitat loss, climate change and human disturbance. Their global population trend is currently unclear.
Among booby species, the blue-footed booby remains one of the most abundant and widespread. But continued conservation efforts will be important to ensure their resilience against growing human impacts across their Pacific coast range.