Siskins Galore

 

There is something about birdwatching that I find so rewarding: learning a simple thing, like a species contact call, opens a new world. Although they are regular wintering birds, I don't think Siskins are becoming more common around Hull. It is just that once I learned the beautiful soft, sad 'pew! call, then I am seeing them everywhere, and this year I have really enjoyed watching Siskins. 

Siskin feeding on Italian Alder this afternoon.

In the depths of the winter, when days are gloomy and cold, Siskin flocks rove around the city looking for Alders. They feed on both Common and Italian Alders, clinging from the cones sometimes upside down, deftly extracting seeds with their pointy bills. In quiet areas they might come down and feed on seeds on the ground.

In the last few weeks, the chattering singing chorus of Siskins have alerted me to flocks feeding in Lombardy Poplars in three different locations around the city, possibly as the seeds in Alders are becoming depleted. I was intrigued as I thought these catkins were pollen catkins. Lombardy Poplars are male clones, which produce red pollen catkins. Being wind pollinated I didn't think they had nectar (which would be odd for a finch to eat anyway), but I've never heard of a bird feeding on pollen. What are they feeding on then? Insects, possibly aphids, is a possibility, but it appears unlikely so early in the year.

Male Siskin feeding on Lombardy poplar catkins.

So, a bit like the Goldfinches feeding on lichen covered branches, I don't have an answer to what Siskins are feeding on, but Lombardy Poplars are plentiful around the city parks and playing fields, where they are planted as wind breakers, so hopefully they will stay around a little longer.

Please do let me know in the comments if you know the answer to the mystery!

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