Busarellus nigricollis
Silhouette: Sheatherius · PhyloPic
In 3 days ~10%
The black-collared hawk (Busarellus nigricollis) is a species of bird of prey in the family Accipitridae. It is monotypic within the genus Busarellus. It has a widespread range of presence, from western Mexico to Uruguay. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, and swamps.
The adult black-collared hawk has a more or less white head, tinged with buff, and with black shaft streaks on the crown. The body, above and below, and the mantle are bright cinnamon-rufous, paler on the chest. There is a black crescent on the upper breast. The back has scattered black shaft stripes; the flight and tail feathers are black with the base of the tail barred with rufous. The eyes are bright reddish brown, the cere and bill black, and the legs bluish white. Immatures are similar, but blotched with black, including on the crown, and the rufous barring on the tail is more extensive. The pale area on the chest is also more clearly marked. The upper surface of the wings is barred, and the eyes are brown.
The nest is usually placed in a large tree, frequently near water, but sometimes in shade trees in coffee plantations or suburban areas. The nest is lined with green leaves. The female lays three to five eggs, dull white, spotted with pale yellow-brown or red-brown and a few darker freckles. There is no further information on its reproduction.
The black-collared hawk lives on a diet mainly composed of fish. It also eats water bugs and occasionally other large insects, snakes, lizards, frogs, snails, other molluscs, crustaceans, small birds and nestlings, rodents and other small mammals.
In the 1870s, Ridgeway wrote that Busarellus (then known as Ichthyoborus) had the "general form and appearance of Buteogallus aequinoctialis", but that it "is much more nearly related to the heliatine groups", in which he included Milvus, Haliastur, and Haliaaetus. During the early-to-mid 20th century, Busarellus was conventionally placed near Buteogallus in taxonomic order.
The black-collared hawk has the basal phalanges of the inner toe fused, which may be an adaptation to prevent the toe from bending back when catching prey. This feature is shared with Ictinia and with the group of true milvine kites and sea eagles (Milvus, Haliastur, Haliaaetus, and Icthyophaga). Research in molecular phylogenetics during the early 21st century indicates that there is a clear milvine–haliaetine clade that is related to a large group of buteonine hawks and their relatives. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Parque Estadual Encontro das Águas | 🇧🇷 Brazil | |
| 2 | Iberá National Park | 🇦🇷 Argentina | |
| 3 | Amacayacu National Natural Park | 🇨🇴 Colombia | |
| 4 | Tortuguero National Park | 🇨🇷 Costa Rica | |
| 5 | Anavilhanas National Park | 🇧🇷 Brazil | |
| 6 | El Impenetrable National Park | 🇦🇷 Argentina | |
| 7 | Manu National Park | 🇵🇪 Peru | |
| 8 | Darién National Park | 🇵🇦 Panama | |
| 9 | Cuyabeno Wildlife Reserve | 🇪🇨 Ecuador | |
| 10 | Tikal National Park | 🇬🇹 Guatemala | |
| 11 | Yasuní National Park | 🇪🇨 Ecuador | |
| 12 | Tambopata National Reserve | 🇵🇪 Peru | |
| 13 | Soberanía National Park | 🇵🇦 Panama |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Barranquilla | 🇨🇴 Colombia | |
| 2 | Santa Cruz de la Sierra | 🇧🇴 Bolivia | |
| 3 | Asuncion | 🇵🇾 Paraguay | |
| 4 | Campo Grande | 🇧🇷 Brazil |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Aviario Nacional de Colombia | 🇨🇴 Colombia |
Rare
Under 5% of wildlife watchers report a Black-collared Hawk sighting in Asuncion on a given day, based on 30 verified sightings from GBIF citizen-science data. It is the 146th most-seen of the 224 birds we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
December
In that month about 10% of wildlife watchers report a Black-collared Hawk in Asuncion on a given day, against under 5% in January to November, the lowest months. That is one of Asuncion's wettest months, with about 180 mm of rain against 40 mm in August.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Black-collared Hawk sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 4
Of the 4 cities where we can rate Black-collared Hawk sightings, Asuncion ranks 3rd at under 5%. The best odds are in Barranquilla (Colombia, about 10%) and Santa Cruz de la Sierra (Bolivia, about 10%).
Same family: Accipitridae
The closest relatives of the Black-collared Hawk that you can see in Asuncion (family Accipitridae, Hawks, Eagles, and Kites) are Roadside Hawk (about 40%), Snail Kite (about 10%) and Great Black-Hawk (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Black-collared Hawk is recorded against all the birds logged in Asuncion (30 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
