MARSH WARBLER
withy bed, at one end of which the common reed was growing in profusion. The reeds were not infrequently entered by the male who owned that part of the plantation, and by the female also, but, as far as it was possible to judge, solely for the purpose of finding food. The situation chosen for reproduction is clearly not confined to any particular locality, nor is any special tree or vegetation a necessity. We may look for and expect to find the birds in wooded banks, in damp or wet osier beds, in hedgerows or along the banks of a river. The choice of a breeding territory seems therefore to be in a condition of instability similar to that which prevails in the date of arrival in different countries.
As is the custom amongst other migrants, males arrive before females. This does not imply a strict division in the times of arrival of the sexes; the first arrivals are males, but in the latter part of the migratory period the sexes seem to accompany one another. How long after the first males the first females commence to arrive, I am unable to say. Since the species is the latest of the migrants, and it is therefore important that reproduction should be commenced as early as possible after the territories have been appropriated, the period during which the sexes are separated is probably not very great. Mr. Warde Fowler is of the opinion that males arrive in Oxfordshire a few days only before the females, and this agrees with my own experience in Worcestershire, which nevertheless is somewhat limited on this particular point.
Each male upon arrival takes up a certain position in the osier bed, plantation, or overgrown bank in which it has settled; and this position constitutes a breeding territory which is adhered to, and more or less defended from intrusion so long as the young require the care of their parents. One instance only has come under my notice of a male occupying a territory, singing there regularly, but ultimately deserting the locality, and I am inclined to think that the cause of desertion in this particular case was the fact that the position chosen was not altogether suitable to the needs of the bird.
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