Wednesday, 20 May 2015

The starlings jump

Today there was a clamour of 'charr!' calls from adults and fledgling starlings in my street. Several families of starlings accompanied from their noisy offspring fed on the verges. The young ones watched their parents and appear to move in slow motion compared to their frantic parents foraging on the grass and then feeding their young. Occasionally passers by would idadvertently scare the birds and the families would become separated. The young called from trees and roofs until they got together with their parents again. A fledgling spent some time on a tree, probing - in that unique starling style - with its bill open, on leaves and branches around it.
busy parent with head down and watchful young.
Probing, tasting, leaves 
Young starlings have a heron-like look to them
more calling!
its a big bad world out there

Tuesday, 19 May 2015

Mallard male-male forced copulation

Mallards are notorious for their unorthodox sexual practices, which include same sex mating and necrophilia (of Ignobel Prize fame, see reference below). This morning, in the apparent absence of a female, four drakes mallards took it on an unfortunate one. I have previously watched apparently consensual male-male copulation in mallard, preceded by courtship, but in this case they behaved exactly like when a gang of males carry out a forced copulation on a female. The series is not very clear, but these are the best I got.

...and the harassed drake eventually flew off! 
I do wonder if the many non reproductive pairs and trios that are now found away from water around the verges of the avenues and even on campus, where there is no pond, are actually seeking some peace and quiet from all this pond sexual excitement.

More information
Moeliker, C. W. The first case of homosexual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae). Deinsea 8 (2001): 243-247. here.

Wednesday, 13 May 2015

Carrion Crow cawing display

I haven't blogged on Carrion Crows this year at The Rattling Crow, and that needs to be amended. So today, I bring you a sequence from this morning, when I documented a Cawing Display. This is a series of movements carried on when cawing from a prominent perch, often by territory holders. The whole body arches and bows as the same time that they call loudly, giving the impression that they put all their might into it. This pair were sitting initially close together and I thought they were getting ready to preen each other, but then they must have spotted an intruder in their territory, as they started performing the cawing display in amazing synchrony. Each display involved cawing and bowing three times, while fanning their tails, and keeping their belly feathers raised. I noticed that in many of the photographs (see the top one, in the middle of a caw) the nictitating membrane - which makes their eyes look cloudy - was drawn at the same time that they called, something that is only possible to notice with photographs.
The pair watching intently. Their tails are touching and slightly fanned and their belly feathers are also a bit ruffled.
The start of a caw.
The end of a caw.
The intruded came closer and both birds called noisily and gave it chase.
Carrion Crows pair for life, which is often not that long (average 4 years, with a maximum recorded age of 9) and the pair remains together all year round. Only territory holders breed, with one year old birds and non-territory holders often moving in a flock and intruding in territories in search of food, leading to squirmishes with the territory holders, in which both members of the pair participate.

More information
Coombs, Franklin (1978) The Crows. B.T. Batsford Ltd, London. 255 pp.

Friday, 8 May 2015

Canada geese head tossing

The Canada geese with a broken wing is now in the company of his partner in the park, who didn't leave with the flock in early March to their breeding grounds. He managed to retain two other individuals for a while - maybe offspring from previous years, as Canada Geese have long term family ties - but they ended up leaving. This morning, somebody started feeding the birds on an end of the pond, and I saw the pair of Canada swimming towards the feeding point. Broken Wing was leading his partner. He kept tossing his head every few seconds, and after a few tries I managed to capture the behaviour (above). It felt like a 'hurry up, follow me!' beckoning to female. Indeed, Canada Geese often communicate using head movements. I have covered the pre-flight head tossing, which is accompanied by much calling. When on land, and during the flightless phase of chick rearing during the moulting period, head-tossing by itself indicates readiness to walk or swim and is used especially when they are very motivated to move. Head tossing is very conspicuous due to the white cheek patch, and this is often directed to family members. Individuals head-toss when stationary, appearing to signal to other family members to follow them, including females to young goslings, and the signal is continued during movement. The direction at which the head is tossed is also informative, indicating the direction of movement. Even young goslings - who don't have the white patch - start head tossing in the first day after hatching, signalling their intention to move to other foraging patch. In a situation of threat, e.g. when a predator is located, this visual signalling allows parents to quietly direct their goslings to cover, avoiding attracting unwanted attention by acoustic signals.

More information

Jeffrey M. Black and James H. Barrow, Jr. (1985) Visual signalling in Canada geese for the coordination of family units. Wildfowl, 36, 35-41. Available here.

Song thrush portrait

The thrushes are now feeding chicks, and there is a sense of urgency when they look for food. They would be shy when not breeding, but now they feed just by you, oblivious to their surroundings. This Song Thrush stood and run, alternatively, on the grass near me, when feeding.
Standing proud
And catching what it looks like a ground beetle larvae.

The moorhen family

Since I first saw the moorhen chicks for the first time, I have only seen one adult with them. The adult apparently decided to build another nest by the island, as the chicks couldn't return to the tree nest. It left the chicks on their own for periods of frantic nest building. The nest is now pretty much done and attracting much attention from the new pair of coots in the park (previous post). I've never seen the chicks on the nest. The number of chicks went from three to two on the 1st of May, but the two left are growing.
One of the chicks had a good look at me.
The young rush to meet their parent for some food.

Thursday, 7 May 2015

A coot pair settles

Two of the coots have stayed in the park and today my suspicions that they were a pair were confirmed. They have shown a lot of interest on the nest that the moorhen who nested in the tree has built at the base of the tree on the water, on the free time allowed by the care of its now two chicks. But that will be something for a different post. On the top shot, one of the coots examines the moorhen nest closely.
Shortly after, the Coot was chased away by the Moorhen, the nest owner.
One of the coots calls the other with a trumpet-like call.
This morning, both coots were near each other. One of them picked a piece of stem and carried it to a clump of vehetation on the shore and rearranged it using her feet and bill. Then, the other coot approached and gave it chase closely, with the first coot swimming to the shore, standing and adopting the curious position of a receptive female, head curled down under her chest. The male then clumsily climbed on top, although he fell down before completing the copulation. I get the impression these are first time breeders, and the breeding instinct is just kicking in. The following are a couple of shots of coot mating pairs taken in another local park where coots are plentiful, illustrating the female position. They often mate on or near the nest. When they are on the water, the female actually submerges her head.