You know those teenagers who seem to eat like a horse but never put an ounce of weight on (I remember the days!)? Well, watching the birds at the feeders today was just like that.

In particular, my male Blackcap seemed to spend almost all the day sat in the fat feeder inside the squirrel guard - peck, peck, peck. I thought he might get to the point where he wouldn't be able to get out.

Much of the time he had to share the feeder, either with my two House Sparrows, with Great Tits, Robins and Dunnocks, or as here with the male Blackbird. (The latter has to be ever alert in case the dominant female spots him and comes barging in - he is pretty scared of her, I can tell you).

Of course, the need to feed like a glutton is a sign of the huge energy demands of these cold days and long, even colder nights on small birds. Research on tits has shown that they need to eat the same number of calories as their body weighs in grams (so an 11g Blue Tit, for example, will need to eat 11 calories a day, which would be the equivalent of me having to consume 70,000 calories a day. Even I couldn't manage that).

That means our garden birds have to undertake an almost constant search for food; every day is a question of survival. It is where garden bird feeding - which I know most of you do - can be a real lifeline.

As well as feeding fat balls, I also feed nyger, peanuts and seed, and this is where I unashamedly plug the RSPB “Fair to Nature” certified sunflower hearts that I've just started using,

They are only just out, and the idea is that the farms the RSPB sources its birdseed from must meet rigorous conservation standards, set by Conservation Grade.

For example, Fair to Nature farmers must have at least 10% of the area they farm as wildlife habitats.The RSPB has always been careful where it sources its birdfood from, but this takes our sunflower seed standards to the highest level.

It's lovely to think that my birds are happy, but the place where their seed came from is full of happy wildlife too.

If you want to drop by my RSPB wildlife gardening blog, it is updated every Friday, and I'd love to see you there - www.rspb.org.uk/community/blogs/hfw