Saba is home to some 60 species of birds, including many seabirds. Along the north coast you will see dozens of Red-billed Tropicbirds, which are nesting and roosting in the steep cliffs. With 750-1,000 breeding pairs, Saba has the largest breeding population in the Caribbean and 12% of the global population. Brown Noddies and Boobies breed on Green Island, a tiny island near the airport, in late spring. Other seabirds worth watching are the Magnificent Frigatebird and the Osprey. Birds of prey include the American Kestrel, which is fairly common, and the Red-tail Hawk, which soars high overhead along the mountain slopes searching for prey. The shy Trembler is not common but can be observed at higher elevations in the rainforest. Early risers may be able to spot the rare Bridled Quail Dove on one of the rainforest trails. The Red-necked Pigeon, threatened by hunting on many islands, is rather common on Saba. There are three species of hummingbirds, the largest of which is the Purple-throated Carib, found mostly in the rainforest. A checklist of the birds of Saba is available at the Ecolodge.