Moorhen: first brood of 2011

Parent with five of the six chicks

The Moorhen (Gallinula chloropus) breeding season is already underway: the first brood of the year, consisting of 6 chicks, appeared in one of several regularly-monitored irrigation basins in Tazacorte on Feb 13.

Information on this species has appeared previously in this blog, but here is a brief summary of the figures:

In 2009, 5 irrigation basins were monitored and a total of 13 broods detected, with 49 chicks hatching altogether, of which 10 were observed to survive until they eventually left their respective ponds as fully-independent young birds.

In 2010, the same 5 basins were monitored plus 3 others. Altogether, 18 broods were detected with a total of 67 chicks, of which 14 survived until they finally abandoned their ponds as independent juveniles.

The percentage of surviving chicks from the total number hatched is remarkably similar in both years: in 2009, 20.4% and in 2010, 20.8%.

As a matter of curiosity, the first brood of 2010 was discovered slightly later in February, at a different location, and also consisted of 6 chicks, of which 2 survived.

Both parents feed the recently-hatched chicks, most of which fail to survive, due to factors outlined in previous posts.
(see 28 Jul 2010 and 16 Dec 2009)

Annual Ardeidae Census - RESULTS

Mouth of the Angustias Ravine on the west coast of the island

The results of the Annual Ardeidae Census were better than expected on the west side of the island: at least three communal roosts have been identified, and smaller numbers of Little Egret (Egretta garzetta) and Grey Heron (Ardea cinerea) were also counted at other sites.

As suspected, some birds of both species fly past the mouth of the Angustias Ravine from early evening onwards, and then head up the coast towards Tijarafe. The precise location of the roost remains unknown, but is probably somewhere on the cliffs opposite the offshore fish-farm (see previous post). One of our observers positioned on the old quay at Puerto de Tazacorte, on the evening of Jan 28, counted 51 Little Egret and 5 Grey Heron flying northwards over the sea at low altitude.

The old harbour wall at Puerto de Tazacorte, looking north

Another member of the our team visited the Dos Pinos reservoir, shown below. Although up to 35 Grey Heron have been recorded around the inner rim of this large irrigation basin in the past, on Jan 28 only 9 birds turned up. Prospections carried out a few days earlier revealed similarly reduced numbers. Perhaps higher counts have included contingents of birds on passage, and not only overwintering individuals.

Dos Pinos reservoir, south of Los Llanos

The recently-discovered roost in Tazacorte, featured in the previous post, yielded a total of 52 Little Egret and 1 Grey Heron, from 18:00h to about 19:25h, when light conditions made further counting impossible. The solitary Cattle Egret spotted on Jan 19 was not recorded on the evening of the census.

The Little Egret roost in Tazacorte. Birds spend the night in the tops of the banana plants located above and to the right of the irrigation basin. The photograph was taken on the evening of the census, from my chosen vantage point.

Other sites where significant figures were obtained:

Los Barros, a mainly avocado-growing and residential area above Los Llanos, yielded a total of 12 Little Egret and 3 Grey Heron in the vicinity of the numerous irrigation tanks.

The floating cages of the fish-farm in Tijarafe added a further 14 Little Egret and 12 Grey Heron.

TOTAL FIGURES FOR THE ISLAND:

134 Little Egret + 35 Grey Heron

Annual Ardeidae Census

Fish-farm off the west coast (Tijarafe)

January 15 was the target date for the annual census of Ardeidae, a nationwide effort promoted by SEO/Birdlife to quantify members of the heron family over-wintering in Spain. Figures for the island of La Palma are still pending, but should be available by the end of this month.

To carry out the survey, observers are required to station themselves at known roost sites before sunset, and count members of the relevant species as they fly in to spend the night. In the case of La Palma, only two species of Ardeidae are involved: the Grey Heron (Ardea cinerea) and the Little Egret (Egretta garzetta).

One of the locations which previously attracted large numbers of this latter species was the fish-farm off the west coast of the island, shown above: over 70 Little Egrets were regularly seen flying to and from the cages anchored offshore. However, during a recent visit to the site, I counted only a dozen birds or so, plus a handful of Grey Herons. The two images below, taken in March 2008, give an idea of the former abundance.

Flock of Little Egret heading for the cliffs

Large numbers of mainly Little Egrets opposite the fish-farm

It is unknown whether such impressive numbers of Little Egret continue to feed and/or roost on the west coast, but some birds can still be observed flying out of the Angustias Ravine in the evening, and then heading in a northerly direction towards the cliffs of Tijarafe. Further field-work is obviously required to ascertain present-day numbers.

During recent prospections a new communal roost has come to light, in rather surprising surroundings. A few days ago I counted 47 Little Egret and 1 Cattle Egret (Bubulcus ibis) flying into the banana plantations shown below late in the evening.

In the centre of the following image is an irrigation basin, hidden from view between the two parallel breeze-block walls. The Egrets tend to arrive from 18:30 onwards, often perching on one or other of the walls, before finally settling down for the night in the tops of the banana plants!

Recently-discovered Little Egret roost

The main roost itself is located in some of the least accessible banana plantations in the whole area, on land which is strictly private property and well walled-off and gated. However, some of the peripheral roosting sites can be reached without trespassing, and the two photos below were taken from a nearby irrigation canal.

Appearance of some of the banana plants used by Little Egret as roosting sites

Sightings in November and December 2010

Group of 6 Tufted Ducks (Aythya fuligula)

Migratory ducks tend to arrive on La Palma later in the year than waders. There have been several interesting species on the island this autumn.

A group of 6 Tufted Ducks (Aythya fuligula) appeared in Las Martelas on Nov 25. Within a few days, two of the birds had left the group, possibly to find themselves another pond, or perhaps to continue their southward journey. At the time of writing, 3 birds remain at their original location.

The solitary Garganey (Anas querquedula) above was also photographed in Las Martelas, and is possibly still on the island, although has not been seen recently.

The rather drab Gadwall (Anas strepera) above has been in Las Martelas since Oct 29, but was recently joined by a group of 4 shown below, which arrived on, or just before Dec 12.

Group of 4 Gadwall (Anas strepera)

I assume the above bird is a Eurasian (Anas penelope), rather than an American (A. americana) Wigeon, simply because of the reddish-brown tones on the head and neck. First seen on Nov 25, the bird is still on the island.

However, on Dec 18, two individuals were discovered at different locations. They eventually joined up in the same basin, as can be appreciated in the image below. The second bird to arrive is much greyer in colouring....a female, perhaps?

Even out of its full breeding plumage, the Shoveler (Anas clypeata) is an unmistakable species.

The following male, moulting into winter plumage, was photographed in Las Martelas on Dec 4.

Shoveler (Anas clypeata)

There have also been up to 18 Common Teal (Anas crecca) in Las Martelas in recent weeks, and, at the seawater pools near the airport, the juvenile Bar-tailed Godwit (Limosa lapponica) was discovered on Nov 18, later to be joined by a second bird. Both are still present at the time of writing.

My apologies to all followers of this blog for the lack of new posts in recent weeks. I am presently experiencing serious technical problems with my Internet connection at home, and am having to use other people's computers and Cyber Centres. Hopefully the problems will be solved by early 2011.

A third American Golden Plover!

American Golden Plover (Pluvialis dominica)

The juvenile American Golden Plover (Pluvialis dominica) shown here is the third example of this neartic vagrant I have observed on La Palma this autumn. The two previous birds were both discovered in freshwater irrigation basins in Las Martelas, and one of them is still to be found there at the time of writing.

This third example, however, was seen feeding at the seawater pools opposite the airport, on the east coast of the island, on Nov 6. The relevant plumage details can be clearly appreciated in this series of images, and identification and distribution of this long-distance migrant have been briefly covered in previous posts.
It is perhaps interesting to reflect that P. dominica was not separated from P. fulva until relatively recent times. Present-day populations of the former are estimated at 10,000-50,000 individuals, despite heavy hunting in the past. The post-breeding migration route is typically an ellipse, in which the outward journey from the arctic and subarctic tundra of North America initially follows the east coast of Canada southwards, crosses the Caribbean, and eventually reaches wintering quarters in Argentina, with the return journey being routed further to the west.
Most remarkably, it appears that the leg from Canada to South America is covered in a single non-stop flight, which, in fair weather, is estimated to take 37 hours. Hardly surprising then, that vagrants turn up in Europe, and other parts of the world, fairly frequently!

Up to 2003, only 28 records of dominica in Spain had been accepted by the Spanish Rarities Committee: 12 in the Canary Islands, and the remaining 16 on the mainland.

The above information has been taken from Aves Raras de España (Eduardo de Juana, Lynx Editions, 2006), a catalogue of bird species of occasional occurrence in Spain. The book includes a table of all records accepted by the Spanish Rarities Committee up to the year 2003.

A second American Golden Plover

American Golden Plover (Pluvialis dominica)

On Saturday 23 October, I discovered this juvenile American Golden Plover (Pluvialis dominica) in Las Martelas, and the bird was still there today, Oct 25, when these three photographs were taken.

The second example of this North American migrant to appear on La Palma so far this season, two birds have also been recorded on Lanzarote in recent weeks: see appropriate links in Canary Islands Bird News for more details.

Plumage details of the previously-detected adult bird were harder to appreciate than in the present case: in the above photograph, there's no mistaking the four primaries projecting beyond the tertials, with two extending beyond the tail end.

This species "breeds in North American Arctic and subarctic tundra, and migrates south through interior North America, or via Hudson Bay, to reach the coast around New England, then over the Atlantic to South America, with the non-breeding season being spent in northern Argentina and Uruguay" (Shorebirds of the Northern Hemisphere, R. Chandler, 2009).

Presumably it is during that "over the Atlantic to South America" part of the migration route when certain individuals go astray...especially in autumns as stormy as the present one.

The Spanish Rarities Committee is receiving an unusually high number of records for assessment this year, including the country's first Bobolink (Dolichonyx oryzivorus), a transatlantic passerine currently located on Lanzarote.

Another North American vagrant at the saltpans

White-rumped Sandpiper (Calidris fuscicollis)

The saltpans at Fuencaliente recently attracted yet another North American migrant: following the Semi-palmated (Calidris pusilla) and Buff-breasted Sandpiper (Tryngites subruficollis) of two previous posts, on the evening of Oct 21 I discovered a solitary White-rumped Sandpiper (Calidris fuscicollis), feeding together with 3 Sanderlings (Calidris alba).

The island of La Palma actually holds the Spanish record for the largest single influx of this particular Nearctic wader, with 6 birds in Las Martelas on Oct 10 2005, 9 individuals at the Fuencaliente saltpans, and 4 at the seawater pools near the airport on the same date! (Ardeola, 54/2)

Note the wing tips projecting beyond the tail

Body size is somewhat smaller than the two Sanderlings shown above, and much more elongated in appearance.

The pale brown colouring on the underside of the bill, and the white rump which gives the species its name, can be clearly appreciated above and below, respectively.

This record will be submitted to the Spanish Rarities Committee in due course.

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