Moorhen 2009 (Part 2)

June 6th, basin B: second brood of 3 chicks.

The following information is based on an observation period of 8 months (from early May 2009 to mid-December 2009), during which 5 different irrigation basins in the municipality of Tazacorte were regularly monitored.

As stated in the previous post, the Moorhen (Gallinula chloropus) is a prolific breeder, but mortality rates are high due to a number of factors:

• Unpredicatble, drastic changes in water levels of 1 - 3 metres, dictated by irrigation requirements, can render nesting sites and available cover untenable.


• Chicks are easy prey for opportunistic predators such as cats, rats, Grey Heron, Little Egret and Common Kestrel.


• Inadequate breeding sites sometimes chosen by parent birds (basins with insufficient food resources, or with high, vertical sides and lack of floating material, so that flightless chicks are unable to leave the water once in).

The number of broods per basin is listed below, together with the number of chicks per brood, and the number of successfully-reared birds. Figures are given for breeding success in each basin, and for the overall breeding success in all 5 basins, expressed as a percentage.

Basin A had 3 broods of 4(June), 7 (July) and 5 (Sept) chicks.

None of the 16 chicks survived more than a few days.

Breeding success = 0%

Basin B had 3 broods of 5 (May), 3 (June) and 2 (July) chicks.
1 chick was successfully reared from the first brood and 2 from the third.
Breeding success = 3/10 = 30%

Basin C had 2 broods of 4 (May) and 1 (July) chicks.
1 chick was successfully reared from the second brood, none from the first.
Breeding success = 1/5 = 20%

Basin D had 2 broods of 4 (May) and 3 (July) chicks.
2 chicks were successfully reared from the first brood, none from the third.
Breeding success = 2/7 = 28.6%

Basin E had 3 broods of 1 (May), 5 (June) and 5 (July) chicks.
1 chick was successfully reared from the first brood and 3 from the third.
Breeding success = 4/11 = 36%

Overall breeding success = 10/49 = 20.4%

Moorhen 2009 (Part 1)

The Moorhen (Gallinula chloropus) is described in the Atlas de las Aves Nidificantes en el Archipiélago Canario (Ed. J.A. Lorenzo) as having a small resident population on the island of La Palma, and reference is made to recent observations of individual birds, evidence of both successful and unsuccessful nesting, and the detection of chicks and juveniles still attached to their parents at various sites.


The following notes are based on the monitoring of 5 different irrigation basins in the municipality of Tazacorte; each one was inspected approximately 70 times during an eight month period, from early May 2009 to mid-December 2009.


Observations show that the species is well-established at specific locations on the island, and is a prolific breeder, with 2 - 3 broods per year.

Two images of the only surviving chick from a brood of 5 born in early May.

This bird eventually left the basin in late July.

A healthy-looking juvenile Moorhen

There was remarkable brood synchronisation in mid-July: the breeding pairs in all 5 basins had either a second or third brood on, or very close to, July 16th.

Cooperative care of chicks by siblings from previous broods was observed in three of the basins (B, D, E).

Although floating platforms of pond weeds were built by some birds, final nesting sites were always on dry land in undergrowth, on concrete steps or manmade structures, or else well-concealed in Rumex lunaria bushes, with the floating platforms being used merely for temporary refuge or as resting areas.

Building a floating platform from water weed

Heading for the nesting site on dry land

A commonly-employed escape strategy when danger threatens. The sequence of 3 images shows a juvenile re-emerging, after remaining motionless for several minutes with only its head above water.

Early December 2009

Osprey (Pandion haliaetus)

Photo: Isidro Brito

Coot (Fulica atra)


Greenshank (Tringa nebularia)



Pintail (Anas acuta) + Coot (Fulica atra)

Nothing new on the island so far this month, but on 05/12 Isidro Brito managed to observe and get excellent photographs of the juvenile Osprey (Pandion haliaetus) which has been around for several weeks. The bird perched twice to devour two small fish caught in a nearby irrigation tank.

The solitary female Pintail (Anas acuta), first detected on 28/11, has been rediscovered in a neighbouring basin, in the company of a large domestic duck.

The female Shoveler (Anas clypeata) can be found at the same location in Tazacorte, but the male Teal (Anas crecca) was no longer there on the evening of 09/12.

Otherwise, there are small numbers of Greenshank (Tringa nebularia), Green Sandpiper (Tringa ochropus), Common Sandpiper (Actitis hypoleucos), and 45 -50 Coots (Fulica atra) in the Martelas area, with a single Redshank (Tringa totanus) at the saltpans in Fuencaliente.

End of November

Osprey (Pandion haliaetus)

Female Pintail (Anas acuta)

Spotted Redshank (Tringa erythropus)

On 28/11 a solitary female Pintail (Anas acuta) appeared in a basin in Las Martelas presently occupied by 45 -50 Coots. This "rare and irregular winter visitor, recorded on all main islands except La Gomera", according to Birds of the Atlantic Islands (T. Clarke, Helm), had gone by the evening.

After temporarily "losing" the Spotted Redshank (Tringa erythropus), the bird was rediscovered at another irrigation basin together with the male Teal and female Shoveler shown in an earlier post (25-30/11).

Finally, on 30/11 I came across the juvenile Osprey (Pandion haliaetus), which has been on the island for a few weeks, being mobbed by gulls at the Dos Pinos reservoir. In the photo, the bird can be seen making off with the remains of a recently-caught fish.

Osprey

Various images of Pandion haliaetus

The Osprey (Pandion haliaetus) breeds in small numbers on Tenerife, La Gomera and El Hierro, with only sporadic nesting elsewhere in the Canaries. On La Palma reproduction has not been confirmed, but the species is seen from time to time inland, and along sections of the coastline. The presence of old nests at certain points on the sea cliffs suggests that the species formerly bred on the island. (Atlas de las Aves Nidificantes, Ed. J.A.Lorenzo).

Inland, near Los Llanos and Tazacorte, the bird feeds on carp which have been introduced into some of the irrigation basins. From my enquiries, it would seem that some banana plantation workers have occasionally seen the bird fishing in their reservoirs, while others react with disbelief at the mere mention of the bird's name, "Fishing Eagle" in Spanish.

This year, I was lucky to spot an Osprey on 26/03, but unlucky not to have my camera prepared. It wasn't until 23/10 that I had another uncertain, distant sighting. Then Xabier Remirez reported and photgraphed an immature bird in Las Martelas on 24/10. On all three occasions, kestrels were mobbing the visiting raptor mercilessly.

Today, 23/11 I had a further encounter with the species and was able to get a few shots for the record. Close scrutiny of the photos above reveals that the individual was a juvenile, with traces of white on the back feathers and a finely cross-barred tail without the darker trailing band.

Late November 2009

Eurasian Teal (Anas crecca). Male

Shoveler (Anas clypeata). Female

Spotted Redshank (Tringa erythropus)

Tringa erythropus

Tringa erythropus

On the evening of 21/11 I had my second sighting of a Spotted Redshank (Tringa erythropus) on the island of La Palma.
A number of identifying features of this attractive wader can be clearly appreciated in the photos: the long bill with its subtly downwards tilting tip - the red being restricted to the lower mandible - and the species' obvious willingness to wade in relatively deep water. The irrigation basin where this scarce migrant was feeding is now being filled with water, so unfortunately this bird will be forced to move on.

22/11: The first ducks of the season! Usually arriving later than the waders, Eurasian Teal (Anas crecca) are fairly common in winter. Small flocks of mostly females and immature birds often spend short periods on the island, moving around in search of suitable basins to dabble in. The flashy male Teal and the female Shoveler (Anas clypeata) shown above were sharing an irrigation basin with two Coots.

In the same area, Tazacorte, there were also three Black-headed Gulls (Larus ridibundus), a fairly regular visitor in winter.

Spotted or Common Sandpiper?

The Spotted Sandpiper (Actitis macularia) is very similar in most plumages to the Common Sandpiper (Actitis hypoleucos). There have been several recent records of macularia on the Canaries, including one (17/10/1996) at the Fuencaliente saltpans, precisely where I saw the bird shown in the photos.

This solitary sandpiper has been at its present location for several weeks and has been confidently reported as Actitis macularia by at least one visiting birder. I still haven't seen the bird in flight or heard it call, two important aids to clinching identification, but the general shape, length of tail projection and absence of dark notches on edges of tertials would seem to tip the balance in favour of the Spotted, rather than the Common Sandpiper.

Any comments from birders with experience of the two species would be much appreciated.