Monday, 19 June 2017

Mobbed by crows

In my way to work as I crossed the park I saw a pair of crows with a fledgling. The young one hopped to one adult and was fed. I took my camera out and started taking photos, but all feeding and begging stopped. The young one started looking around for tidbits on the grass. One of the adults, after eyeing me (the one in the background above), flew to the top of the tree under which I was standing, and cawed loudly and repeatedly. The other adult followed. I didn't think much about this until I carried on with my walk and the crows flew from tree to tree above me, calling all the way, sounding pretty angry. It took that for me to realise that I was being mobbed! I thought about the episode by Konrad Lorenz when his tame jackdaws apparently mistook his wet swimming trucks, which he was holding, by a dead jackdaw and actually attacked his hand, drawing blood. I saw my black camera with dangling cap and immediately put it away. I do hope the crows don't remember me tomorrow!
 Curiously, but not surprisingly, this call is completely different to the mobbing call uttered when chasing sparrowhawks or gulls away (the call that gave name to this blog), which is a dry rattling. Instead is a long, harsh caw. I found a video of a crow attacking a fox and using the same call.
The adult, on the right, eyeing me. 
The young crow stops feeding, as the adults caw above me. 
The young crow is taking everything in, looking at the parents reaction.

Thursday, 15 June 2017

Stock dove driving

Stock Doves are so intriguing. A combination of shyness and a superficial resemblance to feral pigeons makes them often pass unnoticed. Several times this spring I have watched them in flight, usually a pair, sometimes trios, with one of the doves flying right above another, their wings almost touching, but there didn't seem to be aggression in the behaviour. What are they doing?
 I might have found the answer today, reading an old article by Derek Goodwin. He describes a behaviour called 'driving' which is present in several members of the pigeon family, including the domestic pigeon. This is his description:
The driving cock follows his mate everywhere, often literally "treading on her tail". He pecks, usually in a gentle manner, but sometimes fiercely, at her head. If the hen takes wing he flies closely behind and above her. If she goes to the nest (domestic birds) the male stops driving.
Pigeon breeders thought that driving meant that the male pigeon wanted the female to go to nest, given that when the female goes to the nest the driving stops. Goodwin disagreed with this interpretation and thought instead that driving allowed the male to keep the female away from suitors, either on the ground or in flight.

In the two photos illustrating this post, a third pigeon was flying out of frame. I presume the male is the individual above, intercepting the female from the male.

Goodwin observations were consistent with this, as driving happened when other males were near the female, in particular during a period before egg laying and ended once the first egg has been laid, that is, a period when the female is sexually receptive, so that the behaviour is the way the male keeps the female away of competitors, and is effectively a form of mate guarding, as he put it 'It functions to prevent insemination of the female by males other than her own mate. Interference with copulating pairs is part of the same behaviour-complex as driving and has a like causation and function.' When, occasionally, driving was observed with just the pair involved, he thought that the male had succeeded in his driving: 
I have seen a pair fly up from some crowded feeding ground, and the male, who was at first driving hard in flight, swing out beside or in front of his mate as they got well away from others in the air, usually going into display flight as he did so.
More information
Derek Goodwin (1956) The Significance of Some Behaviour Patterns ofPigeons, Bird Study, 3:1, 25-37, DOI: 10.1080/00063655609475836.

Stock dove take over

Yesterday the insistent, zebra-like call of a stock dove just outside the house called my attention. It was atop the Tawny Owl box. We've got the box occupied by the owls since the beginning of the spring, and I presume that they fledged their young earlier as they have been quiet in the last couple of weeks. It's funny that the owls took over the repaired box from Stock Doves and now the doves are back. He was there just now, calling again. The doves should have enough time to raise at least a couple of clutches.

Wednesday, 14 June 2017

Carrion crow fledgling

The Carrion Crow pair in the local park have fledged two young. One of them sat on a carpet of poplar fluff, looking sleepy, and unable to fly very high. It looked like it had flown the nest a bit early. It was very tame, and allowed me to crouch by it and take his portrait. You can see that the chest and head feathers lack the metallic lustre of the adult plumage and the young's eyes are blue. The wing feathers are more metallic. A parent was nearby, furiously chasing a squirrel away. The sibling was much more active, and was intrigued by water, it opened it's bill to the water, like it was testing it or finding out what the best way of drinking was.
The inquisitive sibling. 

Wednesday, 5 April 2017

Encounters of the Sparrowhawk kind

I treasure encounters with Sparrowhawks as they are quite secretive and alert birds which don't like being seen. Today I managed some sightings of a pair in my local park. First I heard a call 'kikikikiki!' and I saw a female landing on a tree. The view was quite obstructed and unfortunately, she flew off as I tried to get a better view. 
Then, a while later, in the same area I spotted the male. Not sure how, possibly a blue tit alarm call alerted me. He had some prey, what looked like a small bird, and was plucking it.
 He flew off, carrying the prey in his talons, and I wandered after him towards some big trees where he had disappeared. Then I saw the pair together, high up the crown of one of the largest trees in the park, a poplar (top shot). Fortunately the beautiful light made up for the distance to take some photos. The male started preening. I couldn't see if the female had the prey now. Male Sparrowhawks hunt for the female while she incubates.
The male at the top, smaller and with reddish tones in his plumage. The female at the bottom, all alert. Soon tree foliage will completely obscure views of these birds from the ground.
 On my way back from work I looked longingly at the poplar. No Sparrowhawks to be seen there. But then, beyond the tree, high in the sky, the pair was circling together, playfully chasing and soaring.


Blackbird mob

Returning home in the light evening today I noticed Blackbirds 'chinking'. This is a very persistent call, often by several individuals, that I usually associate to summer evenings. The blackbirds, up to four of them, were in the tree where the Tawny Owl nest box is. The owls are indeed in occupation, although they were nowhere to be seen from the ground. They have been calling at dusk, and every few days I have been able to watch one of them as it called, sat on the box for a few minutes and then left to go hunting. Often, later at night, one calls with a lovely gurgling sound from inside the nest. Two of the blackbirds got close to the entrance, calling non stop, if there was an owl in the nest, they might be able to see it. At some point they calmed and left, but then one returned, started calling and the others joined him in the tree.
I wondered that the 'chinking' is not a roosting call, but a mobbing call to an owl, which is more likely to be encountered active as nights become lighter in the summertime. In a couple of weeks, the leaves would obscure the view and although a blackbird calling is evident, a quiet owl sitting inside a tree is not. This is a lovely clip of blackbirds mobbing a Tawny Owl demonstrating the call and also how fearless they are towards the owl.

UPDATE 7 April 2017. From the living room at 20:05, I heard a Blackbird suddenly starting to 'chink' and I looked at the nest box. The round silhouette of a Tawny was sitting atop the nest. It was light enough to get a low resolution photo.

Monday, 27 March 2017

Woodpigeons calls and displays

Although the woodpigeon is the bird I come across most often and the one I record the most, it is still one of my favourite birds, the species that made me a birdwatcher. I find them truly stunning and very resourceful, feeling at ease in gardens, parks and woodland alike. Despite their reputation as grain guzzlers their diet includes leaves, nuts (acorns and beech mast), buds, flowers and berries, including rowan, ivy, holly, cotoneaster and alder, which they often reach with great acrobatics. Although Woodpigeons have featured often in this blog, here I am compiling and documenting their calls and displays, especially those related to reproductive behaviour. Although in his article on woodpigeon behaviour Cramp says that 'they mark their ownership of a territory primarily by just being there' as indeed 'a Woodpigeon perched in a tree bare of leaves is a large and conspicuous object' Woodpigeons have a simple, but interesting behavioural repertoire.

Advertisement call. A deep, repeated 5 note phrase that serves as a territorial song. This is the well know Woodpigeon song, often heard early in the morning.

Display flight. This is another territorial display most frequent in February and March. The male flies around the territory rising in a broad arc, and then gliding down with wings held stiffly horizontal advertising ownership. They can do the rising and falling a few times before alighting. Although mainly a visual advertising display, as the bird does not call, sometimes the bird will make a clapping noise with its wings at the apex of the arc.

The Bow display. It is a courtship display that territorial males perform when still unpaired and trying to attract a mate and also when the pair bond is becoming cemented. The male approaches the female and with the his neck is enlarged as he calls a 3 note call as he alternatively stretches its neck and then lowers its head, displaying the white and iridescent neck markings, and fanning the tail when it's highest. Check out this wonderful photo by Richard Hawley showing the display when fanning is at its maximum. Females can display some aggressiveness to the courting male, or move away or flee if they are not interested. This display often happens on trees, roofs or aerials, but occasionally on the ground. When on the ground the male will try and get closer and follow the female hopping to bow just in front of her.

Allopreening, billing and mating. Feeding the mate, gentle preening and billing precedes mating. I documented this behaviour in a series of photos here.

Slightly opened wings is a threat posture.
Fighting. Woodpigeons have very powerful chest muscles, which power their explosive take off and fast flight, and they also use their wings in territorial fights. Males will fly towards intruders landing in their territory and land adopting an aggressive stance, with neck stretched, flattened plumage and semi-open wings, and often this is enough to drive the intruder away. Occasionally, this develops into a fights, which sometimes occur in the depths of a tree. The pigeons will land near each other, alight their bodies and flap trying to hit each other (above).      
                                           
Nest calling. This is a call by the male signalling to his partner a suitable nest site. I've covered this on other posts (here and here) and it is described in detail in the article by Cramp cited below. The call is harsh, and guttural composed of two notes, here is a recording of the call. I want to share here a video I took this morning, in which I got a good angle. You can see pecking or nodding movements to the nest floor in between calls:




More information
Cramp, S. Territorial and other Behaviour of the Woodpigeon. Bird Study 5, 55–66 (1958). here.