("tir-whi-whi-whi-whi-whi") may express distress, or, at least, perturbation.
The Great Plover pursues and catches moths certainly, and other insects probably, whilst they are flying, with great eagerness and dexterity, sometimes making jumps into the air after them, in doing which it aids itself, if necessary, with its wings. Possibly it sometimes flies after a moth, &c, that rises beyond its reach.
An abundance of insects about produces, in these birds, more diurnal activity than would otherwise be the case.
If the one word is to exclude the sense of the other, then the Great Plover cannot strictly be called either diurnal or nocturnal. It would seem to be more the latter than the former, but di-nocturnal would be a more fitting word (did it exist).
Migration begins early in October, but it is not till between the middle and end of the month that all the birds are gone.
The whole flock does not depart together, but in two or more bodies (the larger first), with an interval of several days between them. But stragglers (or rather laggards) are left, and these may go singly, or in small groups.
The Great Plover is an eminently social bird.
- This does not apply merely to their congregating in the autumn. They show, generally, a liking for each other's society. The breeding season modifies this to some extent, but they begin to come together again as soon as it is over.