Black kite: a versatile bird of prey

The black kite (Milvus migrans) is one of the most impressive and emblematic birds of prey that can be found in the skies over Portugal. This fascinating species belongs to the Accipitridae family and is renowned for its impressive wingspan, agile flight and vital role in the ecosystems it inhabits.

The black kite, or black millet, has a dark plumage ranging from dark brown to black, a lighter-coloured head, splashes of grey and a strong, black curved beak. Its reddish-brown or even black breast, and the long, cut-out brown forked tail – earning it the epithet cod tail – are some of the features helping us identify it. With long, narrow, curved wings and a wingspan reaching up to six feet, this is a large species flying in the Portuguese skies.

The black kite has excellent flight skills and quickly changes direction when necessary, namely when spotting prey. It travels at low altitude and lightly, and we can see it chasing other birds in the skies, causing them to lose the food they have captured. This species can also be seen as it soars in the skies taking advantage of updrafts.

Whereas these birds choose tropical and mild temperature regions (Eurasia, Africa and Australia) in the rest of the world to live in, in Portugal they can be seen virtually all over the country, from north to south, coming from sub-Saharan Africa to protect from the winter. In Portugal, their numbers are significant in the Alentejo provinces and in the Central region of the country and they are practically absent in Extremadura and the Algarve provinces.

Versatile, the black kite adjusts to a wide range variety of habitats, from forests, cork oak or holm oak forests to coastal areas and urban areas, namely dumps and landfills, as long as it finds trees in which it can build its nest, in the vicinity of watercourses and wetlands, such as reservoirs, dams and plains. It was found that the black kite prefers wetlands and riparian ecosystems, breeding along rivers and tributaries, namely the Mondego, Tagus, Douro, Tâmega and Vouga rivers.

It is a monogamous and usually solitary species, sometimes forming large flocks, taking advantage of thermal currents flying side-by-side with other species, such as the stork. In the breeding season, prefers to build its nests in the same area, creating colonies. It spends many years with the same specimen; however, in the case of migratory populations, this monogamy is thought to be seasonal. It nests only in mainland Portugal between March and June and lays the eggs in April.

As for its habitat, the black kite chooses large trees to build its nest, close to the top of the tree canopy, in forests or open fields, as long as they are, as mentioned before, located near lakes, thus ensuring easier access to water and food. They can occupy the same nest year after year, restoring it or building a new nest from scratch. This species collects branches to build the outside of the nest; the inside is covered with cloths and rags, papers and other waste.

In each laying, the female lays 2 or 3 cream-coloured eggs with brown spots, hatched for up to 32 days. The female remains close by, while the male is charged with the task of bringing food. However, chicks are fed by both parents and become independent after around two months in late June and early July. Juveniles are ready to start their first flights when they reach six weeks of age.

The black kite is an opportunistic predator with a diverse diet, including small mammals, rodents, birds, reptiles such as the rattlesnake, which it encounters in the fields, and invertebrates such as the earthworm. Sometimes it’s also a scavenger, feeding on the corpses of other prey, and is also often seen watching the roads in to take hold of the animals killed by trampling. It also feeds on aquatic species, fish that it finds afloat in rivers.

Although relatively common in many areas and defined as “Least Concern” (LC), the black kite is a protected species: this species is listed in Appendix II of the Berne Convention and Appendix IIof the Bonn Convention, related to the Conservation of Wildlife and Natural Habitats in Europe, in Appendix II-A of the Washington Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Birds Directive.

This species faces significant threats, including habitat loss, pesticide poisoning and collisions with human infrastructures such as power lines. There are several conservation efforts and management guidelines in place aimed at defending this species, such as the protection of natural habitats and public awareness of the importance of birds of prey, which are essential to ensure its survival.

Did you know that…

In Portugal, in addition to the black kite, there is another kite species: the redl kite. To differentiate the black kite from the red kite, one must look well into it: the black kite exhibits a darker plumage and the tail is brown instead of reddish. The forked tail is the main distinguishing feature helping us tell this species from the dark-phase bald eagle (dark-phase referring to some individuals of that species with darker colours),

This bird belongs to the Accipitridae family, which also includes other birds of prey such as the common buzzard (Buteo buteo), the Bonelli’s eagle (Aquila fasciata) or the snake eagle ((Circaetus gallicus), hawks and goshhawks (Accipiter spp.).