Monday, March 26, 2012

When bad weather brings the migrants down, especially the males

Easterly winds, grey skies and showers at this time of year tend to bring down migrants at Gibraltar. Here they can feed in the olive scrub and woodland, sheltered from the wind. Many have just crossed the Sahara and are ready to feed and drink as they await better weather. This past weekend saw a large arrival of migrants.

Among the main species were Blackcaps Sylvia atricapilla. These large, pale, long-winged birds (above) rapidly outnumbered the greyer local birds (below) which are now breeding. The latter soon gave up trying to chase all the newly arrived males from their territories!

Most of these early migrants are males aiming to set up territories ahead of the females. The latter will dominate the migration later on

Willow Warblers Phylloscopus trochilus (above) and Chiffchaffs P. collybita (below) were also numerous

Males also dominate the Common Redstart Phoenicurus phoenicurus (above) component at this time but Nightingales Luscinia megarhynchos (below) are more difficult to separate 

Male Subalpine Warbler Sylvia cantillans completes the male-dominated migration

Wednesday, March 14, 2012

In the Land of the Iberian Lynx

Two of us (Geraldine and Clive) spent a few days in the stronghold of the world's most endangered cat - the Iberian Lynx Lynx pardina. This animal was familiar to us from the fossils we have excavated in prehistoric and medieval sites in Gibraltar and we had had a couple of close encounters with them in Donana in the 1990s. So we decided to travel up into the Sierra Morena north of Andujar to see if we could find old friends.

The habitat of the lynx can be described as open Mediterranean forest though we prefer to call it wooded savannah, a habitat that was typical of the emerged coastal shelf off Gibraltar for thousands of years. Here in Andujar, there are tens of thousands of hectares of this wild country, home of Spanish Imperial Eagles Aquila adalberti, Black Vultures Aegypius monachus and Black Storks Ciconia nigra.

Among the smaller species, Hoopoes Upupa epops (above) and Dartford Warblers Sylvia undata (below) are abundant and widespread.

Red-legged Partridges Alectoris rufa abound here too and are potential prey of the lynxes.

But it is the Rabbit Oryctolagus cuniculus that is the favoured prey, and there are lots in these hills.

For two days the lynxes were proving elusive, only distant views down the valley confirming their presence. But other predators of the rabbit made themselves visible. Geraldine took time to focus on a large adult Ladder Snake Elaphe scalaris

...and the mating dance of the Iberian Wall Lizards Podarcis hispanica.

As the sun started to go down on our last evening we turned our attention to the herds of Red Deer Cervus elaphus, not wanting to admit defeat to ourselves but knowing that there would have to be another time for the lynx.

Then, driving back with a wonderful evening light a movement caught our eyes as two lynxes wandered into Cistus scrub to our left. We saw them for a split second and they were gone! Fifty metres down we paused by a firebreak in hope as the animals had been moving in that direction. Five minutes went by and nothing. The light would soon fade. Then, out of the Cistus emerged a female with a yellow collar, barely 50 metres away! She sat down and waited for her one-year old cub who promptly sat close to her. Cameras were clicking frantically by then as the lynxes seemed more interested in some Magpies Pica pica than in us. This is what we got...

Collared female (left) and one-year old cub (right) with Magpie (middle ground) and Red Deer (background)!

Female (above) and cub (below)

Now the sun could set!

During our stay in these hills we stayed at Villa Matilde which we thouroughly recommend. Our hosts - Merche and Roland - are committed and knowledgeable conservationists. They took wonderful care of us and the evening meals were wonderful! On our return to Gibraltar an email from them confirmed than the collared female had been born in 2008 and was known by the name Elam...

Tuesday, March 6, 2012

Peak Migration of Short-toed Eagle

For over a week now we have seen a most wonderful spectacle - the spring migration of raptors across the Strait of Gibraltar. Many species are now coming through but the star of the show has been the Short-toed Eagle Circaetus gallicus. Many thousands have passed north and today's migration was spectacular. The birds coming through are all adults that are heading for their breeding grounds in Iberia and beyond.

Adults are easy to identify by their heavily barred plumage and dark heads.

Strong westerlies drifted many of these majestic birds towards the Rock of Gibraltar. Flying over the sea in these conditions is hazardous and the birds were visibly exhausted on arrival.

Soon, all the adults will be back in their breeding territories and the short-lived spectacle will be over for another year, but other species will come in instead. Spring raptor migration now continues until June!

Sunday, March 4, 2012

Species Profile - The Eurasian Black Vulture

Today we start a new section of our blog, dedicated to species profiles. We start with the Eurasian Black Vulture Aegypius monachus.

This species is a solitary tree nester that survives in good numbers across large tracts of Central Spain, in Sierra Morena (Andalucia) and parts of Extremadura in particular.

In these remote forests and dehesas (parklands) they share the territory with another Iberian tree nesting jewel - the Spanish Imperial Eagle Aquila adalberti.

The Black Vulture is a species that is typical of the forests of the mid-latitude belt, from Iberia eastwards into Central Asia. Its success has been the exploitation of trees as nest sites, keeping it well clear of the colonies of cliff-nesting Griffon Vultures, and allowing it to reach carcasses ahead of the Griffon.

This has given rise to the established, but false, idea that Griffon Vultures are subordinate to Black Vultures and must wait the arrival of the powerful Black Vulture to tear into the hide of dead animals. While a Black Vulture can oust a Griffon Vulture in a one-to-one contest, and it can even barge into a group, the reality is that it gets easily overwhelmed by a mass of Griffons and often stays along the edge of the activity picking up scraps.

Though considered sedentary, Black Vultures will disperse southwards in autumn and some regularly cross the Strait of Gibraltar between Europe and Africa.

The old territory of al-Andalus remains Europe's stronghold for this rare species, the largest of Palaearctic vultures