Timing of whitethroatSylvia communisarrival, breeding and moult at a coastal site in Lincolnshire

Abstract

A population of Whitethroats, breeding on the Saltfleetby‐Theddlethorpe Dunes N.N.R. at high density, was studied during 1981–90 by means of mist‐netting. The first adults returned from Africa in late April, with the majority arriving during May. Males were trapped on average eight days earlier than females, and adults of known age were caught slightly earlier on their second or later return than on their first return. Breeding commenced shortly after arrival with peak egg‐laying in the second‐half of May, declining steadily to late July. Recently‐fledged juveniles were trapped from 10 June to 1 September, with a clear peak during 16–30 June. Post‐nuptial moult commenced from late June, with most adults starting in July or early August; moult completion occurred from mid August to late September. Post‐juvenile moult commenced before completion of post‐natal growth, or very shortly afterwards, and took about 36 days. Some late‐fledged juveniles may have moulted more rapidly, retaining a higher proportion of their natal feathers than earlier fledged birds.