A Disappeanance of Crows

Suddenly we only seem to have one crow living in our vicinity. Until December we had something like 20 or 30.

We have had many, many crows for many, many years - as long as we have known our darling Maggie, in fact. Yet now, just as Maggie became ill, the crows have all departed for other pastures, at least for now.

Are the two connected? As far as I can see, magpies shouldn't want crows in such numbers close to their home trees where they raise their young, because crows are very much bigger and they like eating eggs! But on the other hand we know Vicky and the crow mother did a deal in 2007 to swap nests in 2008, so the two species obviously do interact on a constructive basis much more than naturalists give them credit for. Had Maggie done some deal way back, to encourage the crows to live nearby? And did the deal end when Maggie could no longer do his part to hold up whatever it was that was his end of it? Apart from guesswork, the only concrete fact I can think of that relates to the question is that Maggie has always made a game out of taking a piece of food into the middle of a gang of crows and getting it"stolen" from him by the crows. In fact, he has taught each generation of his children how to play this game. First get a big bit of food, then land where the crow will obviously see you, wait until he chases you, act scared, drop the food, and run away a few paces. What is the advantage of that to a magpie? Unless the crows are also doing something for you, and this is how you encourage them to stay nearby?