Friday, 31 August 2012

August Raptors on The Strait

After a few weeks of westerlies and some lovely cooler weather the Levante or easterlies returned this afternoon with it's usual stopping power. Already many raptors are backing up prevented from crossing during the day. Perhaps there's a lull and during the evening or early morning birds can take a chance to cross to Africa but this is always fraught with danger if the wind kicks in again.

Short-toed Eagles are always one of the largest eagles we have that never fail to give close views when on migration on The Strait of Gibraltar.

A very fresh looking Short-toed Eagle passes us by in the early evening

Another juvenile bird shows off his very neat and fresh plumage.
There have been a few Lanner Falcon sightings around Gibraltar and along the Strait in the last few weeks. All, as far as I understand have been juvenile birds like this one I photographed in La Janda a few years back

Black Kites on migration.

Booted Eagle, the commoner light form.

Griffon Vultures at a fallen cow.

An adult Egyptian Vulture passes near Bolonia

A juvenile Egyptian Vulture flies past at Tarifa.

This last week has been particularly busy with raptor migration and thousands of Honey Buzzards have now crossed and are making their way south through Morocco.

The Montagu's Harrier is never a dull sight to feast your eyes on and this colourful youngster really is something quite special.

A melanistic form of the Montagu's Harrier was seen this week (Friday 31st) at La Janda.

Black-winged Kites are migrants as well as being nomads and whatever direction they take is usually dominated by explosions in small rodent populations. Many winter in La Janda but they do not have any particular and regular roost. I counted eight birds at La Janda on the 31st August.

Black Kite. The iconic early migrant raptor that has been going through at a recorded rate of a few thousand a day for the past week at just two observation points.
Here are some of the records from observers at both Cazalla and Algorrobo for the 24th - 28th of August 2012 

Sunday, 26 August 2012

Dragonflies and Sunflowers

The cycle of life continues down in the huge depression of La Janda, once a giant freshwater lake, now a mechanised agricultural area. The huge fields of now ripened sunflowers are cut and harvested early in SW Andalucia comapred to that of central Europe. After we returned from our break in Scotland, many of the fields had already been cleared. The sunflower harvest, like anything Man turns his hand to on a grand scale, has an effect as the disturbance it creates causes many creatures problems. All kinds of insects, birds and smaller mammals had made their homes amongst the stalks and drooping heads of these drying flowers now filled with large seeds that will be turned into sunflower oil.

Here along the canal bankings and waterways Green Sandpiper, Common Kingfisher, Little Ringed Plover, Yellow Wagtail and Collared Pratincole nest and raise their broods. Crested Lark and Calandra Lark can also be found through the fields as Brown Hares hide amongst the tall stems. Many mammals are also present and they include Gennet, Egyptian Mongoose, Rabbit, Rat, Field mouse, Shrew and vole.
The harvest of course does disrupt and affect all these creatures as it is such a rapid process of huge disturbance and as many of the animals and insects flee to find cover elsewhere many birds profit from this. One of them that I'll focus on is the Montagu's Harrier (Circus pygargus)

The Montagu's Harrier doesn't really need a lot of food in one day. Monty's can get by with a few large grasshoppers and crickets each day and feed up on the masses of dragonflies that breed in La Janda.

Dragonflies are fast, agile creatures and they too are predators, hunting smaller flying insects. As the sunflowers are cut the dragonfly and other winged insect population moves across to the adjacent rice-fields the sheer numbers of dragonflies is amazin. The hungry Monty's swoop, hover and dance over the lush green fields, snatching dragonflies and the more common darters, perched and guarding their own territories wthin the green stalks of the ripening rice.

I took a sequence of shots of one very obliging juvenile Montagu's Harrier hunting darters. There seemed to have been an explosion of Red-veined Darters this year or perhaps it was just a concentration due to the sunflower harvest and the insects being forced 'sideways'!. Nevertheless the young raptors sharpened their hunting skills on the darters catching and eating lots. I suppose they are a bit like eating prawns. Remove outer skeleton and eat the fleshy inside...

The pure energy of this aerial ballet is fascinating to watch and shows what effort it takes to hunt at close quarters, focusing in on their prey

Hunting behaviour is similar to that of the Marsh harrier, and involves slow back and forth flight close to the ground. When prey is located the bird suddenly drops onto the quarry, with talons outstretched.

These birds do take other prey as well and if an unsuspecting
Zitting Cisticola, lizard, shrew or mouse is spotted hiding in the paddy-field, then...

Named after the early nineteenth century ornithologist Col. George Montagu, Montagu's harrier (Circus pygargus) is superficially similar to the Hen Harrier, (Circus cyaneus).
Females are brown with a whitish rump, juveniles are similar in colour to females but have reddish-brown underparts. Males are pale grey with black wing bars and wing tips, and have a grey rump. This species is generally silent, but can be heard producing a high-pitched 'yik-yik-yik' call in the breeding season.

In western Europe, an estimated 70 percent of breeding pairs nest in agricultural farmlands, especially cereal crops. This makes the Montagu's Harrier a very vulnerable species, and very dependent on nest protection. Bird protection by NGO's (Non Governmental Organisations) participate in their protection, in collaboration with concerned landowners. Once a nest is spotted in a field, it can be safeguarded either by relocating it to a safer area or by creating a protected space which will not be harvested. In France and in the Iberian peninsula, an average 60 percent of nestlings are saved by this kind of measures.

Quartering along the edges of the water filled rice-field

The Autumn concentrations of Montagu's Harriers, particularly with young birds spending time in the La Janda area and often roosting with other harrier species is a fantastic sight.
During early spring when adult breeding birds return to Europe the displays of bonding pairs is a truly magnificent sight to watch. Montagu's Harriers perform an elaborate range of courtship rituals, similar to those of the Marsh Harrier. The pair circle together at great heights, may pass food to each other, and roll or tumble together, often with talons outstretched.

Breeding pairs are formed when the birds reach about two to three years of age, these bonds can be life-long, but polygamy does occur.

Egg-laying occurs between May and June. The female constructs nests on the ground from grass and sticks. Four or five eggs are laid, and incubation takes about 40 days. After a further 42 days or so the young birds fledge.

Separating females and juveniles in the field is more difficult. Usually the Montagu's Harrier appears more slender and buoyant in flight than the Hen Harrier with a longer tail, longer and narrower wings and more pointed "hands". Also its flight is more elegant than the Hen Harrier, with more elastic, almost tern-like wingbeats.
The distinction between female Pallid and Montagu's Harriers is the most delicate and can only be made in good conditions as the proportions are similar. The best recognition character is the pale collar around the neck of female and juvenile Pallid Harriers which is not present in the Montagu's.
Here's a compilation of photos of wintering Pallid Harriers which shows the distinct boa or collar that you should be primarily looking for to sparate female Hen or Montagu's. Adult Male Pallid, Hen and Monty's are usually pretty easy to identify.

The structure of the Pallid is stronger leaning towards that of the Hen Harrier. The hunting flight of Pallid is not as buoyant as in Montagu's and more akin to Hen Harrier.

Diving down...

A closer look at the young birds fresh plumage.

A young
Montagu's Harrier lands on one of the many raised bankings to feed on a freshly caught darter.

This is a male Red-veined Darter.

This is the

Resting after expending a lot of energy.

The Monty's has a wingspan of 105-120 cms and weighs a mere 0.23 - 0.44 kg

Looking across La
Janda late in the evening.

Monday, 13 August 2012

Scotland - The Bass Rock

The Northern Gannet (Morus bassanus) is a truly impressive bird. It is the largest seabird in the North Atlantic as well as being the largest member of the Gannet family, Sulidae.

Whilst on a family holiday to my native Scotland, we took a nostalgic boat trip from the town of North Berwick, sailing around the Bass Rock and Craigleith on the edge of The Firth of Forth to experience the ultimate in gannet spectacles off this huge basalt column that rises from the sea bed.

Gannets often perform dramatic plunge dives from high in the sky to catch fish up to depths of 30m and can stay submerged for over half a minute. They have no nostrils on their bills and can survive the enormous pressure of such 85kmph dives into the sea without worrying about blowing their brains out!
They also feed from the surface on small shoaling fish like Sand Eels and on discards from fishing vessels, where their large size helps them out compete most other scavenging species. The northern gannet is endemic to the North Atlantic and most breed in Britain and Ireland. There are 21 colonies around the British Isles, with most being on remote offshore islands and stacks, and two on mainland cliffs. Some colonies have been occupied for centuries and are large and conspicuous like the Bass Rock off the East Lothian coast

An adult Shag sits on the lower rocks at the base of the Bass Rock

A Grey Seal pup

The distant Isle of May another great seabird island on the Forth

Gannets wheeling over the top of the Bass

North Berwick

Heading out to sea on the Sula II

The Bass Rock. The white covering is mostly 150,000 of the gannets that breed there although there is some guano!

Canoeists taking a trip out to see the wildlife

Tantallon Castle ruins from the Bass

Wall to wall gannets

Gannets pair for life and only the males build their nests

Over the Bass Lighthouse

In such a cramped breeding area, fights and territorial disputes are common and the noise can be incredible, but then again so can the smell...

Gannet chick being tended to by it's parents

An adult Grey Seal with some facial injury, probably from fighting with other males

Elegant flight

Chick preening