Siskin winter flocks

I have come across a flock of Siskins in my street a couple of times this week. Today, about 20 birds were quietly feeding on seeds of a large Italian Alder (Alnus cordata), a widely planted tree along avenues. They were easily disturbed by car door slamming or a passing dog and tweeted while they flew to a higher tree. Given that my photos are quite distant, I decided to draw a male feeding on alder catkins (above).
Siskins - like Waxwings - are nomadic birds that follow unpredictable resources: tree seeds, with conifers, alder and birch being favourites. In the winter, substantial numbers of Scandinavian Siskins join the British breeding population and disperse more widely. In Scotland, Siskins appear in gardens in higher abundance in years with poor spruce cone crops, indicating more nomadic behaviour in these years and search for alternative food sources. Conversely, they barely come into gardens when their conifer seeds are found in abundance. Sitka Spruce, one of the most widely planted comercial conifer in the UK, has good crops every 3-5 years and this seems to be synchronised across large areas. The large plantations of this tree appear to have benefited Crossbills, Coal Tits and Siskins, which feed on the small seed of the tree. According to the BTO, nesting Siskin populations have increased by 77% since 2004 as the trees in plantations reached maturity and started producing seeds. But Siskins have also altered their behaviour outside their nesting grounds, increasingly using garden feeders - especially peanuts and niger seed - on poor crop years. I wonder if Italian Alder planting in streets might also make easier that we come across this lively little bird.

More information

AILSA J. MCKENZIE, STEVE J. PETTY, MIKE P. TOMS, and ROBERT W. FURNESS (2007). Importance of Sitka Spruce Picea sitchensis seed and garden bird-feeders for Siskins Carduelis spinus and Coal Tits Periparus ater Bird Study, 54, 236-247 : 10.1080/00063650709461480

Acrobatic Woodpigeons and helicopter seeds

The Woodpigeon stately presence might suggest that they are cumbersome birds, but Woodpigeons feeding on trees show that they are surprisingly acrobatic. Compared to their relatives the Feral Pigeons, Woodpigeons have shorter legs and longer tails, which give them more manoeuvrability when moving on branches. Today I saw a group of ten or so feeding on a cotoneaster tree. One of them swallowed one berry rapidly after another while keeping its head low by the bunch of berries, reminiscent of how pigeons drink, keeping their bills under water and swallowing the water directly. 

 Further ahead, three or four were eating seeds in a Sycamore - the ones that fly like helicopters - and having finished off the ones easy to reach, they were balancing and stretching at the end of branches to get at the remaining ones. The individual on the top shot had spent some time trying to reach a bunch of seeds beneath it. It then flew to the branch underneath and stretched its neck in the hope of being able to get them from there.

Planes and goldfinches

This morning coming into work I heard the unmistakable chirps of squabbling goldfinches. There was a large flock feeding on a line of plane trees. While I climbed the stairs I thought delightedly that the window in our lab overlooks the trees, so I could have a level view of the feeding goldfinches. There they were, hanging from the bauble-like seed balls or balancing from the thin stems holding them. London plane trees (Platanus x acerifolia) is an important food resource for goldfinches, as it provides seeds during the autumn months into the winter. The photos didn't come brilliant - I blame the dirty windows - but I think the one on top captures the atmosphere of the feeding flock. I count seven, how many can you see?

More information

Sachslehner, L. M. (1998): The significance of Plane-trees Platanus x hispanica M. as a food resource for Goldfinches Carduelis carduelis L. in Vienna. Egretta 41: 90-101.