Tuesday, 10 May 2016

Collared Dove exhibition flight

Collared Doves have a extraordinary behaviour, their display flight. As males incubate during the day - between 10 am and 4 pm -, and females by night, males are most vocal and active advertising their territory in the early morning and in the evening. Males call their repeated three-note phrase from a prominent perch an aerial or a tree top in the vicinity of their nest. At the end of their call they pause and then launch themselves into a display of pure flight power: climbing almost vertically up to 10 m into the sky, and then gliding down in a broad, long spiral, with wings kept spread pointing downwards, and tail fanned, to finish in the same or nearby spot, sometimes calling a mute trumpet-like landing call. The wing flaps make a soft whistling noise. This sequence can be repeated several times in the early morning and evening. This morning I watched this male sitting on a church top calling, and managed to get the initial jump of the perch into his display flight.
You can watch a slow motion clip of the display flight by redjered here

Monday, 2 May 2016

Greylag nursery

 Many Greylag geese pairs in our large local park have now young goslings. Although geese can be quite intolerant of each other at the start of the breeding season, now the families join together in an area of grass by the lake forming a large nursery. These behaviour might allow them to better detect and defend young from predators. Goslings are precocial and once dry after hatching they can feed by themselves straight away. In the few hours that the goslings spend on their own with their parents they imprint on them and will follow them everywhere. Both parents tend their young by fiercely protecting them from potential predators, hissing or chasing them away, while the goslings feed or rest quite oblivious to their parent's nervousness.
Goslings seek warmth under their mother's wing. Only females are in charge of brooding the goslings in their first few weeks, when they are still unable to regulate their body temperature.
 Despite geese being quite accustomed to people in the park, they still fiercely hiss even as they are being fed. We noticed that pairs differed on how nervous they were. In one of the pairs, the female, instead of hissing, uttered contented calls while she fed and the male didn't hiss at all, despite their goslings being very close to us.
Two families with females brooding young (on the left) and males stand guard.
A group of five goslings follows parents.
Two very nervous parents defending their only young.

Saturday, 30 April 2016

The summer Blackcaps

At the end of April, the arrival of migrant Blackcaps is marked by their beautiful fluty song. Males arrive a few days earlier than females and settle in their breeding territories. I heard the first one in the park on the 19th of April. Blackcaps usually sing from cover in trees and bushes, and the rapidly sprouting leaves will make it more difficult to spot them singing as the spring avances. Today I found a female in the territory where the male had been singing. She was very busy in a tall Sycamore tree, Acer pseudoplatanus, picking aphids from under the leaves, stretching and balancing on the fine branches. The male wasn't far, singing and feeding on aphids like her.
The female feeding.
Note the two aphids on the main veins of the leaf near the male's bill and...
...a few seconds later they are gone.
A short clip of the male feeding.

Thursday, 28 April 2016

Two nest hole snatchers

Some birds make nests from scratch, building them from twigs, branches, spider's webs, lichens or mud. Others need a hole to nest on, and they will use natural holes or those drilled by other birds. This post is about two such 'nest snatchers' I've watched recently. In the last few days, I've noticed starlings moving a lot of back and forth between an Ash and the grass lawns in my local park. Yesterday, they were actually using last year's Great Spotted Woodpecker's nest. Woodpeckers have a reputation for feeding on the chicks of hole nesting birds, but they also might be providing them with the nest hole in the first place.
A photo from last year (24th June), with a chick almost ready to fledge calling to its parent (on the right branch) 
Yesterday, a Starling getting in the hole

 The other nest snatching event happened just in front of my house. There's been an owl box in the Lime tree in front of the house for over 15 years. It was well used, the hooting and gurgling noises of the Tawny Owls from the nest very obvious in the night. A few years ago the bottom of the nest fell off, and the sky was visible from the ground. On Valentine's day the next year the owls called from the nest, probably inspecting it, but it was deemed useless and we stayed owl-less for a few years. This year, Stock Doves showed a lot of interest in the owl house (top shot taken 9th April). They stuffed the box with branches, and miraculously, the branches stayed, the box had been repaired!
The repaired nest, branches sticking out at the bottom.

 The booming call of the Stock Doves greeted me in the mornings as I left for work. Until one night we heard a Tawny Own hooting. The owl was actually sitting atop the nest, calling, then flew off low over the roofs. The owls have been calling regularly since, and I guess they have taken possession of the owl box and evicted the Stock Doves.
 
 Tawny Owl watching us from the nest box (20th April).

Wednesday, 27 April 2016

Incubating crow

The finished Carrion Crows nests are very obvious atop the still bare trees. There are several breeding territories I cross on my way to work. Some of these seem to have used the same nest they built last year, others have built another one nearby, the older one still standing strong. If you are lucky you can get a glimpse of the incubating female's head or tail sticking out of the nest. The top shot, I took earlier today, shows that one of the campus pair have decorated their nest with white packaging material. Their nest, on a not very tall alder, is very visible.
Only female crows get brood patches during the nesting season: two bare and highly vascularised areas on the chest, which are in direct contact with the eggs and make incubation more efficient. These patches are covered with the feathers surrounding them, which the female fluffs open before sitting on the eggs. The male doesn't get brood patches, and doesn't incubate. During this time, the male feeds the female, and sometimes stands guard near the nest, as this poor photo shows. The female's tail sticking out of the nest on the left and the male sitting on the right. During the breeding period, the male is very protective of the nest area, and these days I see them mobbing Herring Gulls and Sparrowhawks that come near the nest.

Sunday, 17 April 2016

Goldcrest singing

There are two territory holding male Goldcrests in my local park. Each appears centred on a large cypress. This morning, over the traffic noise, I head their incredibly high pitched, not very loud song, which appears to come from a tiny violin.
 I searched for it a bit halfheartedly, as this cypress is massive, but the Goldcrest just moved onto a smaller one. It fed, as Goldcrest do, in a rush, never stopping, but it did stop for a moment to utter his song and I managed to capture it.
This is a sonogram from the wonderful website Xenocanto of a Goldcrest song:

Friday, 8 April 2016

Female magpie begging from her mate

The pair of Magpies must be around the egg laying stage. Only the female Magpie incubates, while her partner must feed her during this time. Females start begging for food to her partner around the time that they lay their first egg, noisily, wings flapping and uttering what has been described as the 'clear call'. The success of a pair of Magpies depends on how good the male is at keeping his mate well fed. A hungry female is more likely to take breaks from incubation, leaving the eggs exposed to predators (most likely Carrion Crows, according to T.R. Birkhead, the archenemy of Magpies).
 Yesterday afternoon, I heard this peculiar Magpie call repeatedly from the garden. The pair of Magpies were at a birch tree and one of them (the one on the top, likely the female), flapped her opened wings, chasing and begging to the other, quite indifferent, individual, likely to be the male. I took a video of this behaviour you can watch below (you might need to turn the volume up to hear the call).



More information
Birkhead, T. R. Studies of West Palearctic birds: Magpie 189. British Birds 82, 583–600 (1989).