Rüppell’s Griffon Vulture

RÜPPELL’S GRIFFON VULTURE · Gyps rueppelli

L: 85-100 cm. WS: 230-250 cm. Wing: ♂ ♀ 670-710 mm. Weight: ♂ ♀ 6.500-9.000 g. Longevity < 30 years old.

Coordinators: Alex Ollé & Joan Goy

Taxonomy:

· rueppelli (Narrow strip of sub-Saharan Africa, Senegambia to Sudan and Tanzania).

· erlangeri (Etiopía and Somalia).

Status:

Basically resident, with important dispersal movements. In the early 1990s it began to be detected with some regularity in Morocco and the extreme south of the Iberian Peninsula. It is now a regular bird with dozens of annual observations, especially of immature individuals between August and November, although individuals of any age and time of year can be observed. There are also numerous observations throughout Spain, and exceptionally also in France. These birds come to Europe naturally, through their association with the Griffon Vulture that winters in the Sahel, mainly in Senegambia.

In recent years, several mating attempts between Rüppell’s Griffon Vulture and Eurasian Griffon Vulture occured in Spain and Portugal, although their success wasn’t confirmed until 2023 for the first time. That happened in a colony of Eurasian Griffon Vulture in Málaga (Andalusia), where a male of Rüppell’s Griffon Vulture and a female of Eurasian Griffon Vulture raised a hybrid chick, being likely that these cases may take place more frequently in the future.

Moult:

Second plumage: january to december 2cy. Until September of the second calendar year moults the 4-5 innermost moulted primaries.

Third plumage: from february to September 3cy. By September of the third calendar year it has moulted p6-8, even reaching p9. Most secondaries are juveniles.

During 4cy it moults the last outermost juvenile primaries (p8-9) and p10, and by the end of the period it has moulted most secondaries.

Sexing:

Sexes cannot be identified in field.

Similar species:

Griffon Vulture, White-backed Vulture, Lappet-faced Vulture.

Bibliography:

FORSMAN, D. 2016. Flight identification of raptors of Europe, north Africa and the Middle East. Bloomsbury.

OLLÉ, A. & TRABALON, F. 2019. Aves rapaces de Europa. Omega.

RODRÍGUEZ G. & ELORRIAGA, J. 2016. Identification of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP. Dutch Birding 38: 349-375.

Rüppell’s Griffon Vulture sounds

Distribution

Rüppell’s Griffon Vulture Collages

griffon-ruppells-african-white-backed-vulture-identification-africanus-rueppelli-fulvus

Rüppell’s Griffon Vulture vs Griffon Vulture and vs African White-backed Vulture

Rüppell’s Griffon Vulture vs Griffon Vulture

Booted Eagle

BOOTED EAGLE · Hieraaetus pennatus

L: 42-50 cm. E: 110-135 cm. Wing:♂340-395 mm,♀375-435 mm. Weight:♂510-770 g.,♀840-1.150 g. Longevity: < 15 years old.

Coordinators: Alex Ollé & Joan Goy

Taxonomy:

Monotypic

Status:

It is basically a trans-Saharan migrant, arriving in Europe to nest between the end of March and April, leaving for Africa between the end of August and October.

Some autumns are marked by a variable number of individuals migrating northwards, due to the bad weather conditions encountered in the Strait of Gibraltar. In this way, they perform a loop migration, moving to Africa via Italy. In the years when this phenomenon occurs with greater intensity, the number of wintering Booted Egrets is much higher on the Spanish Mediterranean coast.

Moult:

It does a complete moult every year.

Second plumage (transitional): At the end of May or June of 2cy they begin the moult, which is retained in their autumn migration in September or October. At this time it has moulted the 5-7 innermost primaries, and already in Africa, it finishes its moult in the winter quarters. Some specimens may retain some juvenile primaries until the spring of 3cy.

It seems that wintering birds in Spain do not moult during these dates, so that in the spring of 3cy they show a very late moult extension compared to wintering birds in Africa.

Adult plumage: Adults moult very similarly to the 2cy, starting in Europe and ending in Africa.

Sexing:

Although females are slightly larger, it is very difficult to differentiate the sexes.

Morph:

Two distinct forms or morphs. The proportion of the light morph is lower the further east in Europe, there being a certain relationship with the climate. In Spain, the light morph is present in between 60 and 90 % of the individuals, depending on the area. Those determined as intermediate, belong to light specimens of the dark form.

Similar species:

Egyptian Vulture, Black Kite.

Bibliography:

BOSCH, J. 2019. Clinal polymorphism variation in the Booted Eagle Hieraaetus pennatus: the influence of climate during the breeding season. Bird Study 66.

BOSCH, J., MESTRE, J., BAIGES, C., MARTÍNEZ, J.E, CALVO, J.F. & JIMÉNEZ, M.V. 2019. Colour plumage polymorphism in the Booted Eagle: inheritance pattern and temporal stability of the morph frequencies. Journal of Zoology

OLLÉ, A. & TRABALON, F. 2019. Aves rapaces de Europa. Omega.

Booted Eagle sounds

Distribution

Booted Eagle Collages

Bonellis-Eagle-vs-Booted-Eagle-juvenile-plumage-identification

Bonelli’s Eagle vs Booted Eagle in juvenile plumage

Booted Eagle: evolution of plumages

Bonelli’s Eagle

BONELLI’S EAGLE · Aquila fasciata

L: 65-72 cm. E: 145-180 cm. Wing:♂308-530 mm,♀480-580 mm. Weight:♂1400-2200 g.,♀2100-3025 g. Longevity: < 25 years old.

Coordinators: Alex Ollé & Joan Goy

Taxonomy:

· fasciata: from southern Europe and North Africa, to northern Indochina and southern China, through the Middle East.

· renschi: Lesser Islands of the Indonesian region of Sonda. Some taxonomists consider renschi a separate species.

Status: juveniles and immature birds – up to their 3rd or 4th year – make dispersal flights that vary in length but can reach over 1.000 km from the place they hatched. These birds tend to settle temporarily in areas with high availability of food resources. Adult birds on the other hand, are usually sedentary, expanding their territory only during the non-breeding period.

Moult:

Second plumage: 2cy. From March – May to the end of October. The moult starts with the inner primaries. Usually, they manage to replace the 6-7 innermost primaries and a few secondaries. However, amongst the southernmost populations in the Near East for example, they are able to moult all juvenile primaries.

Third plumage: during late spring through the summer of the 3cy. The juvenile primaries and secundaries that remained unmoulted are finally replaced. Then, another moulting cycle begins starting, once more, with the innermost primaries.

Adult plumage: the moult amongst adult birds usually have two asynchronous fronts, producing an irregular pattern. The females start moulting during the breeding season and before the males.

Sexing: males and females can be separated by size and structure. Females are larger and heavier, with the head proportionally smaller in relation to the body. Additionally, in juvenile plumage the females show a regular dark band across the greater and primary coverts that the males do not have. In adult plumage, the males are overall paler than the females, with 1) larger extension of the pale colouration on the edges of the tail feathers and 2) undertail coverts, tarsal coverts and throat feathers also paler. Nonetheless, or as a result of the paler colouration, the males show more obvious brown or darker streaks or spots than the females. The females have an overall darker colouration.

Similar especies: Booted Eagle, Short-toed Snake Eagle

Bibliography:

GARCÍA, V., MORENO-OPO, R. & TINTÓ, A. 2013. Sex differentiation of Bonelli’s Eagle Aquila fasciata in western Europe using morphometrics and plumage colour patterns. Ardeola 60(2): 261-277.

OLLÉ, A. & TRABALON, F. 2019. Aves rapaces de Europa. Omega.

Bonelli's Eagle sounds

Distribution

Bonelli's Eagle Collages

Bonelli’s Eagle: adult plumage

Bonelli’s Eagle: 3rd plumage

Bonelli’s Eagle: 2nd plumage

Bonelli’s Eagle: juvenile plumage

Bonelli’s Eagle vs Booted Eagle in juvenile plumage