Species of the Week

This week we are going to take a look into this African raptor, the Secretary bird

Common name: Secretary Bird

Species: Sagittarius serpentarius (Miller, 1779)

 

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Accipitriformes

Family: Sagittariidae

Genus: Sagittarius

 

Conservation status: Vulnerable (http://www.iucnredlist.org/static/categories_criteria_3_1#categories)

Diet: Large insects and small animals, mainly rodents. However it feeds opportunistically on any animal it comes across on its wandering travels (ehares, mangooses, squirrels, snakes, lizards, amphibians, freshwater crabs and birds).

Height: average 1.2m

Weight: average 23 to 42,7kg

Wingspan: 1.2 to 1.35m

Average life span in the wild: average 18 years

Range elevation: 3000m (high)

 

A very large and distinctive terrestrial raptor. It is grey, whitish and black in all plumages, with small bill and head, bare face, relatively long neck, exceptionally long bare legs, and long graduated tail with greatly elongated central rectrices. It is known for is distinctive crest of black-tipped spatulate feathers.

 

Geographic Range

Sagittarius serpentarius is found throughout sub-Saharan Africa, except the extreme deserts of the Namib coast and the forested region around the equator in western Africa. Individuals from this species were observed from Senegal and Gambia in the west across to Ethiopia in the east and extending southwards through Mozambique into South Africa.

Reproduction

Secretary birds are monogamous and are thought to pair for life. This species may breed throughout the year, although there are peaks in breeding from August to March. Both male and female will construct a large nest on a flap-topped-tree. Normally, a pair of secretary birds will reuse the same nest for many years, adding to the structure each year, in order to create a nest that can range from 1,5 to 2,5 meters in diameter.

The female lays a clutch of 1 to 3 eggs, with each egg is laid with an interval of two to three days. The incubation of the eggs starts as soon as the egg is laid and is shared by both parents, although the female spends more time with this task since the male brings the food to the nest.

Hatchlings have large heads that seem too heavy for their bodies. At two weeks of age, they attain a thick grey coat and one week later the crest begins to appear. It takes six weeks until they can stand on their own. In 64 to 106 days, the offspring will fledge, remaining around the next tree for more 62 to 105 days, during this time they are still depending upon the parents for food and training.

 

Behaviour

Secretary birds are sometimes solitary, but is usually found in pairs or family groups consisting of up to five individuals. Larger aggregations of this species may form near an abundant food source or a watering hole, however this groups don’t remain together too long.

 

Sagittarius serpentarius become active around two hours after the sun has risen, normally when the grass is no longer wet due to the morning dew. They spend the day walking around and feeding until late afternoon, when they normally return to their roosts.

Threats

  • Spreading cultivation and urbanisation
  • Excessive burning of grasslands
  • Humans disturbances: herders
  • Captured and traded
  • Directed hunting and nest-raiding
  • Predation: crown and ravens, ground hornbills, kites and other raptors, eagle owls

 

Curiosity

  • Eats rodent and insect pests that feed on the crops of the local farmers.
  • They are known to take domestic chickens when foraging in areas close to human houses.
  • Population have been declining.
  • Generally silent species.
  • This species prefer walking rather than flying and they do an average about 20 to 30 km per day on foot.

 

 

References:

http://animaldiversity.org/accounts/Sagittarius_serpentarius/

http://www.arkive.org/secretarybird/sagittarius-serpentarius/

http://www.iucnredlist.org/details/22696221/0

 

Images:

http://www.hartebeestfonteinconservancy.org.za/media/k2/items/cache/007f7dcc1de776ae0fbd86ceae8656ad_XL.jpg

http://cdn2.arkive.org/media/B1/B16C7359-2ACB-449F-B08C-093DEEF56B4F/Presentation.Large/Secretarybird-adult-and-juvenile-in-nest.jpg

https://s-media-cache-ak0.pinimg.com/originals/a3/e3/1c/a3e31c802e46a120722fed6f84581e9e.png