Of Eagles, Rabbits and Partidges

It is quite remarkable how we often observe the world around us without fully appreciating the depth of time that we are observing. Three species are currently staging a "cat-and-mouse" saga that goes back to the Pleistocene. The game is at least 100 thousand years old!

The "cat" in our game is the majestic Spanish Imperial Eagle, an endangered species which is endemic to the Iberian Peninsula. I watched these birds hunting in the plains of La Janda this week.

There are two "mice" in this story. One is a bird - the Red-legged Partridge (above). The other is a mammal - the Rabbit (below). Both are Iberian endemics too. Hard to believe it may be but the Rabbit evolved within the Iberian Peninsula and has been introduced everywhere else by humans!

The eagle is one among a suite of species (including the endemic Iberian Lynx) that have relied to a large degree on these two prey species. Both reproduce quickly and in large numbers and have been an almost inexhaustible supply of food for these predators.

Rabbits are doing particularly well in La Janda, having recovered from epidemics that have reduced their numbers in recent decades. It is wonderful to see families of them sunning themselves close to their burrows under the cover of wild olives (above). Indeed a millennial sight! Rabbits must have been so numerous that they gave Spain its name. The Roman Hispania was derived from the Carthaginian Ispania which is thought to come from the word Sphan which meant Rabbit. Literally Spain means "Land of Rabbits"!

With the big eagles lurking Rabbits rely on camouflage and keeping still (above) to go by unnoticed. Partridges too are cryptic when seen from above or behind (below).

But Nature generates uncontrollable impulses which can expose prey. Partridges calling out to stake out territories may suddenly become visible (below).

...and the eagles are ready to pounce!

their strategy is to dive from great heights (above) or to approach low with stealth (below)

either way it is a long, tried and tested, method with great rewards...

Above: Spanish Imperial Eagle with Rabbit

It's hard to fathom, watching in awe as these animals play out this game of life an death, that the same sight was seen millennia ago by our Neanderthal cousins. They died out and we have put the eagle's future very much on the balance. How much longer will we allow this millennial game to continue to be played in our skies?

Diary - The Common Crane

This is the month when the Cranes that have wintered in southern Iberia and Morocco return northwards to their Scandinavian and Russian breeding grounds. The gathering of thousands of Cranes in traditional spots like the old lake of La Janda might convince us that all is healthy with this species. But reading the accounts of the 19th Century naturalists leads us to realise that we are observing a meagre ration of what was once a real spectacle of nature.

One of my favourite accounts of the northward passage of Cranes across the Strait of Gibraltar is Irby's who wrote how: "On the 11^th of that month (March), in 1874, Mr Stark and myself had the pleasure of seeing them (the Cranes) on passage; and a grand and extraordinary sight it weas, as flock after flock passed over at a height of about two hundred yards – some in single line, some in a V-shape, others in a Y-formation, all from time to time trumpeting loudly. We watched them for about half an hour as they passed, during which time we calculated that at least four thousand must have flown by. This was early in the morning, and we were obliged to continue our journey; but when we lost sight of the Vega of Casas Viejas, over which the cranes were passing in a due northerly direction, there appeared to be no diminution of their number, and, as my friend remarked, ‘One would not have believed that there were so many Cranes in all Europe.’"

Thirty years later Verner commented how the passage was as spectacular as in Irby's day and noted how: 

"The direction taken by successive flocks, in accordance with observations made by me for me for many years in the same district, is almost invariably the same, namely a line which when plotted on a map passes about 6 miles west of the old town of Tarifa."

It is a danger to highlight the spectacle today as it lulls us into a false expectation that all is well. But the real cause of the decline of the Crane is habitat loss. Places like La Janda, once Spain's largest lake and now sadly drained, and many other wetlands of the Strait of Gibraltar were part of a vast network that supported vast numbers of waterbirds of which the Crane was a spectacular flagship. Even as I write these lines wetlands like the Smir on the Moroccan side of the Strait are being filled to give way to developments. This is particularly ironic as this wetland forms part of an intercontinental UNESCO Biosphere Reserve!

The situation is even sadder. Cranes no longer breed in southern Europe but they did in Irby and Verner's day, la Janda being their last stronghold. Verner (1911) tells us how: "About thirty years ago, considerable numbers of Cranes remained to nest in south-west Andalucia: but constant egging by professional “collectors” has sadly reduced their numbers. In some districts they have ceased to nest altogether while in others where I can recall seeing over thirty pairs in the nesting season there are now hardly half a dozen to be found during the summer months."

So these images are a tribute to a wonderful species and its wetland habitats and a warning: just because we see large flocks of this species (or indeed other animals), it should not be taken to mean that all is well. The wetlands of the Strait of Gibraltar and its birds have been dying a long and lingering death for 150 years. Yet it seems that more emphasis is placed on the wonders of the region than on the rate of loss. In another 150 years it may only be the images that we are left with. And that will be our legacy...

Celebrating our First Birthday

We celebrate our first birthday today!

In this first year we have been viewed by close to 4700 individual visitors from 95 countries.

There have been close to 11,500 views of our pages.

In Networkblogs we have achieved a following of 759. In our theme categories we have achieved the second highest following in Nature, third in Environment and fourth in History.

Thanks to all our facebook friends and followers for your support. We will try and build on this in our second year!

Diary - The Lammergeier

The Lammergeier has become among the rarest of European breeding birds. The decline seems to have started as far back as the 19th Century and its causes seem to have been a combination of the rise of guns, poisoning and nest robbing. Colonel Irby in 1895 wrote how his friend Colonel Verner had already noticed a decline twenty years earlier when "...these birds nested regularly not far from Gibraltar, but owing to persecution have of late years disappeared or retired to less-frequented sierras."

Dr Stark, in the decade of the 1880s recorded how "In Andalucia is decidedly common in the Sierra Nevada, and all the region between Granada and Jaen. In a day’s ride five or six may be seen flying over the hill-sides or gliding along the face of a cliff or down some ravine. In the Ronda mountains they are fairly numerous, becoming scarcer towards Gibraltar and Tarifa."

It seems that the presence of the Griffon Vulture was somehow detrimental to the natural distribution of the Lammergeier. Dr Stark thus commented how "In certain districts of the Sierra Nevada, where the Griffon does not intrude, the Quebrantahuesos is especially numerous."

Stark's comments also suggest that the population near the Strait of Gibraltar was dominated by non-breeding immatures (above and below). "In the lower ranges of the Sierra de Ronda, towards Gibraltar and Tarifa, the Bearded Vulture is not very common; the Griffon being, on the contrary, abundant in that district. The majority of Bearded Vultures seen here have been birds in dark plumage, not fully adult."

Today, to have any chance of seeing (and photographing) Lammergeiers we have to travel to the Pyrenees, the main European nucleus of this species. Re-introduction programmes, such as those in the Sierra de Cazorla, offer hope of recovery which will be slow. These birds take eight years to reach breeding condition.

Subadult

First winter (left) and adult (right)

Today, in special places like Boumort in the Catalan Pyrenees, it is still possible to observe the complete array of European vultures together. Three of them - Griffon, Black and Lammergeier - are in this single photograph.

My gratitude to the management and staff of Boumort Reserve for permission to photograph within the reserve

Diary: The Bonelli's Eagle

With the new year I am introducing a new section to the blog called diary. Whenever this word appears in front of the post title it means I will be drawing on written texts from 19th and early 20th Century naturalists and comparing to the present. Photographs may not all be from now but will include some from my archive. Today, I start with the Bonelli's Eagle Aquila fasciata.

This impressive cliff-nesting eagle has attracted the attention of naturtalists for a long time. Sadly, this bird is very much in decline and is rarer each year. The European population is of the order of 1000 breeding pairs, 80% of which are in Spain with smaller numbers in Portugal, Greece, France, Italy, Croatia and Albania.

Its geographical range once included many coastal cliffs where it is now gone. A traditional site was the Rock of Gibraltar where it nested annually until last recorded in 1936 - the disturbance of the war years probably caused their disappearance. They nested below the old Signal Station (below).

Colonel Howard Irby in the second edition of his Ornithology of the Straits of Gibraltar (1895) tells us how " a pair nest annually at Gibraltar, at the 'back of the Rock', to the south of the Signal Station; there are never more than a pair, though there are four situations where there are nests, one of which has not been used for several years.

typical eyrie with two chicks

My friend and colleague Dr Juan Pleguezuelos of the University of Granada studied this habit of use of alternative nests and found that it was a way of avoiding parasite infestation. What is more he was able to show that birds which lined the nests with fresh branches of Maritime Pine Pinus pinaster had a greater breeding success rate. The chemicals produced by this pine acted as an effective insect repellent that kept the nests clean and the chicks healthy!

Bonelli's Eagles were once widely distributed across southern Iberia and our Pleistocene cave sites on the Rock have revealed evidence of their presence since at least 50 thousand years ago (above).

Irby tells us how "when not breeding they hunt together (male and female), one high above the other, suddenly stooping down on some luckless rabbit or else gliding off to take up a fresh aerial station whence to watch for their prey, which seems to be taken on the ground." The other favourite prey of this bird is the partridge.

Irby relates some fascinating accounts of situations and contexts unlikely to be found today. Ospreys also nested on Gibraltars cliffs and he tells us what happened when they came across each other: "on another occasion, in the same month, I saw a Bonelli's Eagle flying about not far from the Osprey's nest, when down swooped an Osprey, like a stone, striking the Eagle on the back and knocking out a lot of feathers. Shrieking out, they were bound together for a few seconds, and then separated, neither apparently the worse for the encounter, and each flying off towards their respective eyries.

Lt Colonel Willougby Verner, writing in 1909, was equally impressed by this powerful eagle. As a falconer and son of a falconer he "was intensely attracted by Bonelli's Eagle when I learnt that it was the same species which the Afghans employ for hawking small deer."

He further observed "as regards their structure, few Eagles, if indeed any, are so powerful for their size as is Bonelli's. Their massive legs and feet and abnormally large claws are seemingly out of all proportion to the rest of their body." 

It is a real pity that such a majestic animal should be suffering such a fate as we progressively eat into their territories and sever traditional connections that have maintained viable populations for tens of millennia...