Category Archives: Field Notes

Everything you wanted to know on the Booted Eagle migration and never dared to ask!

Dark morph Booted Eagle reaching Europe from Africa across the Strait of Gibraltar.

The Booted Eagle is one of the most representative species of the raptor migration in the Strait of Gibraltar. It is a medium sized raptor of powerful flight whose migration has received low attention by the scientific community. This has changed, however, with the recent publication of a comprehensive monograph on the “Migration and spatial ecology of the Spanish population of the Booted Eagle” based on GPS tracking. The work has been conducted within the MIGRA project of SEO/Birdlife and has had the input of a remarkable group of ornithologists from different Spanish institutions. The results have been presented in a beautifully edited open access document in Spanish with English summary.

Booted Eagle in active migration over the ocean in Tarifa.

Birding The Strait has contributed to this project with several photos of Booted Eagles on migration in the Strait of Gibraltar, including the one in the cover. As ornithologist and birdguides in Tarifa we have received this publication with big interest and next we summarize some of the most striking results:

Pale morph Booted Eagle over Tarifa in southbound migration to Africa.

In Spain the Booted Eagle is a migrant species except in the Balearic Islands, where it is resident. Booted Eagles spend 13% of their lives on migration, 42% in their breeding grounds in Europe and 45% on their wintering quarters in Africa.

All migratory routes converge in the Strait of Gibraltar where the average date of arrival is the 17 of September and the 31st of March in their Southbound and Northbound migrations, respectively. Eagles crossed the Sahara in a broad front following similar routes in spring and summer, with no coastal flyways observed. The studied individuals completed their migration in 28 in spring and 23 days in autumn. Interestingly, this pattern opposes the general trend observed in most migratory species, on which the return migration to their breeding grounds is faster than the autumn migration to the wintering quarters. The eagles flew an average of 8 hours a day, covering from 130 to 250 km, with an absolute record of 541km between two consecutive night roosts!

Dark morph Booted Eagle in the Strait of Gibraltar.

Visual counts in the Tarifa area have shown that approximately 71% of the individuals belong to the pale morph while 29% belong to the dark one.

The number of Booted Eagles crossing the Strait has significantly increased within the period 1999-2016 and a similar result has been obtained at raptor watchpoints in the Pyrenees. Nowadays over 30.000 Booted Eagles cross the Strait of Gibraltar to Africa every year.

The bulk of the Iberian population overwinters in the Western Sahel region including Mauritania, Guinea, Mali, Burkina Faso, Niger, Nigeria, Chad, Cameron and Sierra Leona with a remarkable wintering site fidelity in consecutive years.

Pale morph Booted Eagle in Tarifa.

The number of Booted Eagles overwintering in Spain is steadily increasing over the last decades and nowadays it should be considered a scarce but regular wintering species. We recommend to consult eBird to get further insight on the wintering population of Booted Eagles in Spain.

Juvenile pale morph Booted Eagle perched in a powerline which has been isolated to avoid raptor electrocution in La Janda, the Strait of Gibraltar.

The logo of a leading energetic corporation on the front cover may arguably raise alarm bells to critical readers. In fact, Iberdrola has been sanctioned with millionaire euro fines in Spain on account of the electrocution of raptors, including the endangered Spanish Imperial Eagle. Pushing conflicting emotions aside, it is important to highlight that this work identifies and highlights electrocutions and hunting as the two main causes of non-natural mortality for the species.

Pale morph Booted Eagle in active migration in the Strait of Gibraltar.

The global results show the Booted Eagle as a rather plastic species on its foraging, migrating and habitat selection habits with a wide distribution range. It seems likely therefore that thanks to this attributes the Booted Eagle will have a more promising future than other less adaptable species. This work stresses the importance of stablishing integrative conservation measurements including its breeding sites, foraging areas, migration flyways and wintering regions.

Booted Eagle near Tarifa
Booted Eagle in active migration near Tarifa

All in all this work fills an important gap on the knowledge of raptor migration and it is of interest for bird enthusiasts, researchers and decision makers.

International Congress on Bird Migration and Global Change in Tarifa, September 2018

In September 2018, in addition to the most spectacular raptor migration in the continent, the Strait of Gibraltar will host a world-class cast of raptor biologists and bird migration researchers.

The 3rd International Congress on Bird Migration and Global Change will be held between the 3rd and 5th of September in Tarifa. Ian Newton, Willem Bouten, Miguel Ferrer, Francisco Pulido, Keith Bildstein, Bruno Bruderer, William Bouten and Jordi Figuerola will speak on global change and population limitation on migrants, adaptations of birds to global change, birds as indicators of global change, global change and migration behaviour, new tools for study and analysis, side effects of global change and much more.

Follow this link to read the complete programme and further information.

In Birding The Strait we are glad to collaborate with this international  event.

Eagles and Lynxes with Dick Forsman in Sierra Morena

During the third week of January we have organized a scouting trip to Sierra Morena (Córdoba, Andalusia) with our friend and raptor identification authority Dick Forsman. Our main target was to observe large eagles and get a first-hand experience on the performance of especially dedicated wildlife photography hides.

Adult male Golden Eagle. January 2018. 

Working from hides is a radically different experience regarding the “raptors in flight” photography we practise while birding and guiding in our local patch, Tarifa and the Strait of Gibraltar. Pros and cons apart, observing these majestic raptors at such a close range is an unforgettable and, at times, surrealistic experience.

Adult male Bonelli´s Eagle. January 2018.

Nowadays, there is a growing offer of commercial wildlife photography hides in Spain and the ones we have tested, run by Alpasin, have proven to be excellent in all key aspects. We have greatly enjoyed six hide photography sessions in three effective days covering Bonelli’s, Golden and Spanish Imperial Eagle. The two first species performed remarkably well, approaching the hides in no time and beautifully posing at different perches and in different lighting conditions. In turn, the Spanish Imperial Eagle left us willing to try again. This is the point after all!

The constant presence of inquisitive Iberian Magpies, Thekla Larks, Blue Rock Thrushes and Hoopoes enlivened the waiting periods and a photography session at a reflecting pool visited by Robin, Blackbird, Hawfinch, Long-tailed Tit and Blue Tit added diversity and much fun to the experience.

Long-tailed Tit. January 2018.
Hoopoe. January 2018.

Last but not least, we got the exciting chance to visit an Iberian Lynx hide. Never in our wildest dreams did we expect it to go so well…

Female Iberian Lynx. January 2018.

All in all, a highly rewarding experience with like-minded colleagues which no doubt will lead to strengthen our collaborations!

With Agustín Pérez (left), managing director of Alpasin and Dick Forsman (right), after a Golden Eagle session.

PS: Visit our youtube channel to see more on this and other Birding The Strait experiences!

The most colourful Black and White spectacle

The return migration of White Storks in the Strait of Gibraltar peaks in January. Thousands of storks are crossing from Africa these days. Indeed, most of the Iberian population will return in January, wherein older individuals migrate first. Enormous flocks will stop in the rice paddies of La Janda while others will keep moving on their northbound journey.

219 White Storks reaching Europe from Africa across the Strait of Gibraltar. January 2018.

Black kites will be joining the scene in February, crossing the ocean in impressive streams and roosting in even more impressive numbers. See below a video of these roosting kites that we managed to film last spring.

Together, Black Kites and White Stork make up about three-quarters of the soaring birds that fill the skies in Tarifa. And this is only the beginning folks! The raptor and stork migration will not stop until June!

Join our birdguides in a bespoke day trip or tour to live the experience of Tarifa and the Strait of Gibraltar!

Short-eared Owls magic!

Short-eared Owls are captivating creatures. Their penetrating look, silent flight and discrete habits make every encounter memorable.

This is a cosmopolitan species that visits the Strait of Gibraltar both as a migrant and wintering species.  However, their presence in our region is mostly noticeable during the central part of the winter.

Short-eared Owl photographed off Tarifa, the Strait of Gibraltar, in active migration to Africa across the immensity of the sea.

Like other “yellow-eyed” owls, the Short-eared do actively hunt in daytime, especially in the late afternoon. It is at this time when we enjoy watching them hunt passerines at their roosts, chasing Marsh Harriers or stalking unwary mice atop their favourite perch. The magic light of winter sunsets in Cádiz handles the rest!

Join us in a day trip to observe and photograph Short-eared Owl this winter!

It´s that time of the year again!

Griffon Vulture in the Strait of Gibraltar

Late October and November is arguably the most complete birding period in Tarifa and the Strait of Gibraltar. It is in this time of the year when the Griffon Vulture migration is at its best, with over 900 Griffons (including one Rüppell´s) thermalling together this morning in El Estrecho Natural Park.

At the same time, thousands of passerines migrate in daytime to Africa following the coastline of Los Lances beach in Tarifa comprising European Goldfinch, Common Chaffinch, European Serin, Skylark, lagged Barn Swallows and House Sparrows too.

Scopoli's Shearwater in migration as seen from the Island of Tarifa
Scopoli’s Shearwater in migration as seen from the Island of Tarifa

Over the Ocean, good numbers of Scopoli´s Shearwaters (up to 3300 birds/hour have been counted today by Migres) cross the Strait, along with Balearic Shearwaters, Audouin´s Gulls, Skuas and Terns.

In La Janda, the first groups of Cranes have reached their wintering grounds and the puddling of the flooded rice paddies attracts large numbers of White Stork (no less than 3000 this afternoon), Glossy Ibis and Cattle Egrets.

Common Cranes in the rice fields of La Janda
Common Cranes in the rice fields of La Janda

Although the big days of raptor migration are over, the community of birds of prey is remarkable including Spanish Imperial, Bonelli’s, Booted and Short-toed Snake Eagles, Eurasian Marsh and Hen Harriers, Black-shouldered and Red Kites, etc.

Dark morph Booted Eagle in the Strait of Gibraltar.

In addition, October is an excellent period to look for rarities. Proof of this are the two Yellow-browed Warblers which have been found today in the region or the striking male Pallid Harrier and the immature Lesser Spotted Eagle (probably a returning individual) we have seen! All this under a beautiful blue sky and mild temperatures!

Immature Lesser-spotted Eagle at La Janda, October 2017.