Christine's walking & birds blog

Over the years, I've read time and again how birds migrate to the north in summer to exploit the insect-rich environment for rearing their young, with the implication that these are tropical species making special journeys to breed. It never seemed to explain satisfactorily why they come so far, at such risk; and in 2011, I wrote a few paragraphs on migration which put the question: "Is it possible that the ancestors of summer visitors once lived here in the north as resident species?"

I looked out this document because yesterday Greger (I had mentioned my theory to him at the time) handed me his i-pad and said I might be interested in a recent article in New Scientist. This relates how Ben Winger (great name for researcher into bird migration!) and his colleagues "built a mathematical model to reconstruct the geographical ranges of the ancestors of hundreds of living species of American songbird. They found that most long-distance migrants began in the north and started flying south for winter, as opposed to being tropical birds flying north for summer."

This was quite exciting. I'm a bit of a dunce where science is concerned; and feeling doubtful about my theory, I nearly deleted the piece. Other birders have probably come to the same conclusion about migration - but I have to say this is the first time I've heard of it or seen any mention of it in print - so, for once, I thought something out for myself; and, quite unexpectedly, here is some genuine scientific research that says I might just have got it right.

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A white egg appeared to be impaled on the needles of the dwarf pine in the garden. At 3cm long, it's possibly a collared dove's egg.


We have collared doves in the garden all the time, but I can't say I've noticed them nesting in this pine; otherwise, it could, I suppose, have fallen from a nest and been speared by the (fairly sharp) needles which would then have bent over with the weight. But it seems unlikely something predated and then impaled it (I can only think of shrikes that do that) especially as the yolk has been left uneaten. The tiny insect on the bottom of the egg is probably a springtail; but whether that or something else is responsible for the square hole in the shell is a mystery. Later: a springtail isn't an insect as it has internal mouthparts.