A couple of months ago I wrote about the way our local robins seem to target dunnocks, frequently flying the width of our garden to see one off. Robins are feisty little birds and often quite combative toward other species, but the special zeal with which they chase off dunnocks probably has to do with similarities in terms of habitat and food.
But I have noted similar battles between a number of other closely related species. Blue tits, for example, which come a long way down the garden pecking order, will frequently fly at visiting coal tits and chase them away. To some degree size does matter in the garden, and blue tits are among the smallest birds to visit our feeders, losing out to some degree to larger species like greenfinches or for that matter great tits. However, they are persistent, and of course they are quite acrobatic little birds, able to exploit openings some of the other larger species aren’t agile enough to use to their advantage.
Coal tits are just as agile, but don’t seem to do as well at all. I wonder why. They are about the same size as a blue tit, and I imagine they have a very similar diet. Coal tits are very definitely at the bottom of the pile as regards bird feeder pecking order, and only manage to sneak in when other birds have their backs turned. Their strategy is to zoom in, grab a seed and zoom away - and in fact they will hide most of these seeds for later use.
Blue tits show a particular antipathy toward their close relative the coal tit, and I’ve observed them - again, like the robin - flying almost the width of the garden to tackle a coal tit and turn it away from the feeder. I presume once again that it’s because they have such similar needs, in terms of diet and habitat. They can’t help but be competitors.
Recently, I’ve also noticed a similar interspecific conflict between blackbirds and song thrushes. Song thrushes have declined considerably in recent years, so I was pleased to find one beginning to visit us regularly through the latter part of the winter just gone, and into this spring, when in fact there is clearly a pair - good news! But a song thrush has only to hop onto our lawn for it to be attacked by blackbirds. Closely related species, again, with song thrushes a little smaller than blackbirds, and more specific as regards diet.
There are many more blackbirds than song thrushes in our gardens, and it may be that - if what I’ve observed is replicated nationwide - song thrush decline might have to some degree have been assisted by this blackbird/song thrush conflict, even if the primary reasons for decline lie elsewhere as I expect they do. Blackbirds will anyway be assisted by being more generalist feeders. Some have even managed to use our suet feeder. They don’t do it very well, wings flap wildly and then the bird sort of falls off back to the ground - but they do manage to win their morsel of food.
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