Species of bird
This article is about species. For the subfamily of birds sometimes called "Booted eagles", see
Aquilinae
.
The
booted eagle
(
Hieraaetus pennatus
, also classified as
Aquila pennata
) is a medium-sized mostly migratory
bird of prey
with a wide distribution in the
Palearctic
and southern Asia, wintering in the tropics of Africa and Asia, with a small, disjunct breeding population in south-western Africa. Like all
eagles
, it belongs to the family
Accipitridae
.
Taxonomy
[
edit
]
The booted eagle was
formally described
in 1788 by the German naturalist
Johann Friedrich Gmelin
in his revised and expanded edition of
Carl Linnaeus
's
Systema Naturae
. He placed it with the eagle, falcons and relatives in the
genus
Falco
and coined the
binomial name
Falco pennatus
.
[2]
Gmelin based his description on "Le Faucon Patu" or "Falco pedibus pennatis" that had been described and illustrated in 1760 by the French zoologist
Mathurin Jacques Brisson
. Brisson had examined a specimen in the collection of Madame de Bandeville who was also known as Marie Anne Catherine Bigot de Graveron (1709-1787).
[3]
[4]
The booted eagle is now placed in the genus
Hieraaetus
that was introduced in 1844 by the German naturalist
Johann Jakob Kaup
.
[5]
[6]
The genus name combines the
Ancient Greek
hierax
meaning "hawk" with
aetos
meaning "eagle". The specific epithet
pennatus
is
Latin
and means "feathered".
[7]
The booted eagle has no recognised
subspecies
.
[6]
Based on recent
genetic
research some authors reclassified this species to the
genus
Aquila
, along with some
[8]
or all
[9]
other
Hieraaetus
species. As it is the
type species
of
Hieraaetus
, should any of the hawk-eagles have been retained in a distinct genus then a new name for that group would have been necessary. However,
DNA
research has shown it forms a
monophyletic
clade
with
Ayres's hawk eagle
,
Wahlberg's eagle
,
little eagle
and the
pygmy eagle
and this clade is often treated as forming the genus
Hieraeetus
[10]
and most reference lists currently use
H. pennata
.
[11]
[12]
[13]
Although some authors name a number of
subspecies
most now treat it as a
monotypic
species.
[14]
Aquila minut
described by Brehm (1831) is this bird. The
fossil
bird described under the same name by Milne-Edwards (1871) is preliminarily known as
Hieraaetus
edwardsi
, but might belong in
Aquila
.
Description
[
edit
]
The booted eagle is a small eagle, comparable to the
common buzzard
in size though more eagle-like in shape. Males grow to about 510?770 g (1.12?1.70 lb) in
weight
, with females about 840?1,025 g (1.852?2.260 lb) with a length of 40 cm and a wingspan of 110?132 cm. There are two relatively distinct plumage
forms
. Pale birds are mainly light grey with a darker head and flight
feathers
. The other form has mid-brown
plumage
with dark grey
flight feathers
.
[15]
It was found in a study investigating polymorphism that these discrete colour morphs follow a Mendelian inheritance pattern, where the paler allele is dominant.
[16]
In South Africa, 20% of the population is the dark colour morph. Booted eagles are typically seen in pairs or as solitary individuals.
[17]
However, the study found that the darker morphs are much more common in the eastern populations such as in Russia.
[16]
The
call
is a shrill
kli-kli-kli
.
[15]
Distribution and habitat
[
edit
]
The booted eagle has breeding populations in many different regions in both the northern and southern hemisphere. These include southern
Europe
,
North Africa
and across
Asia
, and also in western
South Africa
and
Namibia
.
[18]
The northern populations are
migratory
spending November to February
[18]
in
Sub-Saharan Africa
and
South Asia
, while the small southern African populations is sedentary. This is a
species
of wooded, often hilly countryside with some open areas. It breeds in rocky, broken terrain but migrants will use almost any type of habitat other than dense forest.
[18]
The birds of the Palearctic breeding population tend to nest in coniferous or deciduous woodlands and often in trees.
[19]
Southern African populations
[
edit
]
It is believed that there may be three separate groups of booted eagles in Southern Africa.
[17]
There is evidence of a population which breeds in the south-western Cape region of South Africa, arriving in early August, laying eggs in September, and leaving in March of the following year.
[19]
From about April to July the birds migrate northwards, some possibly overwintering in Namibia.
[17]
A small breeding population in Northern Namibia has also been observed. The third group is a non-breeding population thought to migrate south from Eurasia and North Africa in summer, however no empirical evidence of this has been documented.
[17]
These booted eagle populations are not sub-specifically distinct from those in Palearctic regions.
In South Africa, booted eagles also occur in hilly and open landscapes and in contrast to their Northern Hemisphere conspecifics, typically breed strictly on rocky cliffs in ravines and gorges. However, evidence has been found in South Africa of birds nesting in trees such as Euphorbias.
[20]
This bird is most common in the low stature shrublands of the Fynbos and Karoo, and more specifically the ecotone between the two biomes.
[17]
Behaviour and ecology
[
edit
]
The booted eagle typically flies at relatively low heights, making it conspicuous. However, the dark morph can be confused with other local medium sized birds of prey.
[17]
In South Africa, 20% of the population is the dark colour morph.
Diet and hunting
[
edit
]
The booted eagle typically hunts on the wing, stooping quickly with wings folded in and feet extended.
[19]
It hunts small
mammals
,
reptiles
and
birds
.
[18]
In Southern Africa, it has been noted that birds are the most common prey. It has been suggested that frogs comprise an important part of the booted eagle diet, however this has not been observed in the Southern African populations. Studies conducted in south-western South Africa observed that they ate birds, lizards, and rodents.
[20]
Breeding
[
edit
]
This eagle lays 1?2
eggs
in a nest built from sticks and lined with green leaves in a
tree
or on a crag, or it takes over the disused nest of another large bird such as a
black kite
or
grey heron
. The female incubates the egg for around 45 days and is fed by the male, after hatching she guards the nest and the young while the male provides all the food. The chick fledges after 70?75 days.
[18]
Booted eagles are monogamous and perform courtship rituals of sophisticated flight demonstrations.
[16]
Southern Africa
[
edit
]
The population of eagles which breed in the Cape region of South Africa typically do so shortly after arriving in August. The breeding pairs nest on cliff ledges, this is one of the ways in which this population differs to the Palearctic booted eagles.
[19]
It has been observed that the incubation period for this population is about 40 days, and the nestling period around two months.
[20]
It was found in a study conducted in South Africa that typical to the species, booted eagles nested on cliffs at an average height of 60m. The clutch size was also comparable with Palearctic populations, with pairs generally successfully raising two chicks according to existing evidence.
[19]
The eggs are typically a conspicuous white colour sometimes with red speckles.
[13]
The dimensions of the eggs are consistent with those of Palearctic populations.
[19]
The nests of the booted eagles in Southern Africa also appear to be less rigid than those of their Palearctic counterparts.
[19]
Northern African
[
edit
]
Populations of booted eagles migrate to parts of North Africa during European winter and breed there. A study conducted in Algeria determined that these birds typically incubate their eggs for a period of 33 to 38 days.
[21]
Similarly to populations further North and South, it was most likely for clutches to consist of two eggs (67.6%).
[21]
Conservation and threats
[
edit
]
There is a great lack of research about this migratory species. The Southern African populations were relatively recently discovered in the 1980s, possibly suggesting that they migrated due to changing climate and environmental conditions. Changes in human land use may have driven the changes in migration patterns of these birds.
[17]
It is also thought that this species has been overlooked in Southern Africa due to the remote and discrete nature of their nesting sites.
[20]
This emphasizes the need for further research to fully understand the ecology and conservation status of this species.
References
[
edit
]
- ^
BirdLife International
(2016).
"
Hieraaetus pennatus
"
.
IUCN Red List of Threatened Species
.
2016
: e.T22696092A93543946
. Retrieved
6 November
2021
.
- ^
Gmelin, Johann Friedrich
(1788).
Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis
(in Latin). Vol. 1, Part 1 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 272.
- ^
Brisson, Mathurin Jacques
(1760).
Ornithologie, ou, Methode Contenant la Division des Oiseaux en Ordres, Sections, Genres, Especes & leurs Varietes
(in French and Latin). Vol. 6, Supplement. Paris: Jean-Baptiste Bauche. pp. 22?25, Plate 1.
The two stars (**) at the start of the section indicates that Brisson based his description on the examination of a specimen.
- ^
Thiebaud, Francois (2018).
"Une femme collectionneuse au XVIIIe siecle, Marie-Anne Catherine Bigot de Graveron, Presidente de Bandeville"
(PDF)
.
Bulletin de la Societe Historique et Archeologique de l'Essonne et du Hurepoix
.
88
: 19?37.
- ^
Kaup, Johann Jakob
(1844).
Classification der Saugethiere und Vogel
(in German). Darmstadt: Carl Wilhelm Leske. p. 120.
- ^
a
b
Gill, Frank
; Donsker, David;
Rasmussen, Pamela
, eds. (August 2022).
"Hoatzin, New World vultures, Secretarybird, raptors"
.
IOC World Bird List Version 12.2
. International Ornithologists' Union
. Retrieved
5 December
2022
.
- ^
Jobling, James A. (2010).
The Helm Dictionary of Scientific Bird Names
. London: Christopher Helm. p.
192
,
296
.
ISBN
978-1-4081-2501-4
.
- ^
Collinson, Martin (June 2006).
"Splitting headaches? Recent taxonomic changes affecting the British and Western Palaearctic lists"
.
British Birds
.
99
: 306?323. Archived from
the original
on 29 February 2020
. Retrieved
13 April
2015
.
- ^
According to Avibase,
The Clements Checklist
first reassigned the
Hieraaetus
spp. to
Aquila
in the 2001 revisions to the 5th edition. However, in the 2009 revisions to the 6th edition, four species (including booted eagle) were moved back to
Hieraaetus
.
- Clements, James F. (June 2007).
The Clements Checklist of Birds of the World
(6th ed.). Ithaca, New York: Cornell University Press. pp. 47?48.
- The Clements Checklist team (23 December 2009).
"Updates & Corrections ? December 2009"
.
The Cornell Lab of Ornithology
.
Pages 47-48, Wahlberg's Eagle
Aquila wahlbergi
, Booted Eagle
Aquila pennata
, Little Eagle
Aquila morphnoides
, Ayres's Hawk-Eagle
Aquila ayresii
. All of these eagles belong in the genus
Hieraaetus
- ^
"Booted Eagle -
Aquila pennata
"
. The Eagle Directory. Archived from
the original
on 8 December 2015
. Retrieved
3 November
2016
.
- ^
Gill, Frank; Donsker, David, eds. (2014).
"New World vultures, Secretarybird, kites, hawks & eagles"
.
IOC World Bird List, version 4.2
. International Ornithologists' Union.
doi
:
10.14344/IOC.ML.4.2
.
- ^
"
Hieraaetus
Kaup, 1844"
.
Integrated Taxonomic Information System (ITIS) [online database]
. Retrieved
22 June
2014
.
- ^
a
b
Lerner, H.; Christidis, L.; Gamauf, A.; Griffiths, C.; Haring, E.; Huddleston, C.J.; Kabra, S.; Kocum, A.; Krosby, M.; Kvaløy, K.; Mindell, D.; Rasmussen, P.; Røv, N.; Wadleigh, R.; Wink, M.; Gjershaug, J.O. (2017).
"Phylogeny and new taxonomy of the Booted Eagles (Accipitriformes: Aquilinae)"
.
Zootaxa
.
4216
(4): 301?320.
doi
:
10.11646/zootaxa.4216.4.1
.
hdl
:
11250/2443953
.
PMID
28183111
.
- ^
"Booted Eagle
Hieraaetus pennatus
(Gmelin, JF, 1788)"
.
Avibase
. Denis Lepage
. Retrieved
3 November
2016
.
- ^
a
b
Kemp, Alan; Kemp, Meg (1998).
SASOL Birds of Prey of Africa and its Islands
. New Holland. pp. 104?105.
ISBN
1-85974-100-2
.
- ^
a
b
c
Bosch, Josep (3 July 2019).
"Clinal polymorphism variation in the Booted Eagle Hieraaetus pennatus : the influence of climate during the breeding season"
.
Bird Study
.
66
(3): 306?316.
doi
:
10.1080/00063657.2019.1657064
.
ISSN
0006-3657
.
S2CID
203374811
.
- ^
a
b
c
d
e
f
g
Boshoff, A.F. and Allan, D.G., 1997. Booted eagle.
The Atlas of South African Birds
,
1
, pp.184-186.
- ^
a
b
c
d
e
"
Aquila pennatus
(Booted eagle)"
.
Biodiversity Explorer
. Iziko Museums of Southern Africa. Archived from
the original
on 27 March 2016
. Retrieved
2 November
2016
.
- ^
a
b
c
d
e
f
g
Steyn, Peter; Grobler, J. H. (1 June 1981).
"Breeding Biology of the Booted Eagle in South Africa"
.
Ostrich
.
52
(2): 108?118.
doi
:
10.1080/00306525.1981.9633593
.
ISSN
0030-6525
.
- ^
a
b
c
d
Steyn, Peter; Grobler, J. H. (1 March 1985).
"Supplementary Observations on the Breeding Biology of the Booted Eagle in Southern Africa"
.
Ostrich
.
56
(1?3): 151?156.
doi
:
10.1080/00306525.1985.9639584
.
ISSN
0030-6525
.
- ^
a
b
Bouchahdane, Issam; Boukhemza, Mohamed; Souttou, Karim; Derridj, Arezki (1 December 2019).
"Breeding Biology of Booted Eagle Hieraaetus Pennatus (Gmelin, Jf, 1788): The First Study in North Africa"
.
Ekologia (Bratislava)
.
38
(4): 382?391.
doi
:
10.2478/eko-2019-0028
.
ISSN
1337-947X
.
Further reading
[
edit
]
- Clark, William S. (1?8 November 1986).
The rufous morph of the Booted Eagle
. International Bird Identification: Proceedings of the 4th International Identification Meeting. Eilat: International Birdwatching Centre Eilat. pp. 21?24.
External links
[
edit
]