Within a week of the first sighting, six birds were in residence, with 12 birds by the end of January and a maximum of 22 birds in February.
The arrival of the Treeps in the garden coincided with the winter stubble on the Fen being ploughed in. Presumably they had been feeding on these food-rich stubble fields, which also held large numbers of Corn Buntings, Skylarks and Yellowhammers.
Before the breeding season I put up 16 nestboxes along a line of elms by the house. Come the breeding season, six adults remained and a pair took up residence in the nestbox nearest the house, another pair was in a House Sparrow colony in the leylandii hedge of the neighbour opposite, and a third pair was found in another House Sparrow colony in some nearby farm buildings. In June the first of six broods were seen feeding in the garden, and during the summer at least 18 young were seen.
By October the young had dispersed and I was back to six birds. At the end of October the remaining birds disappeared for a week, then on 26 November, they left altogether.
No birds were seen until 5 January 2004 when two birds returned. By mid-March, 11 birds had returned and six pairs then established themselves for the breeding season. Amazingly, these six pairs all double-brooded, with two pairs (last years adults?) triple-brooding. In total, 33 ‘treebies’ (young Treeps) fledged and spent much of the summer feeding in and around the garden. By late September they started to disperse, presumably into the surrounding farmland which is full of natural food sources. In October I found a small group over a mile away from the house feeding with finches and buntings in a game cover strip which had been planted down the side of a thick hawthorn hedgerow – a cracking combination of food and cover, and it help over 40 Yellowhammers, 10+ Reed Buntings and a couple of Brambling.
The graph below shows the changes in numbers throughout 2003 and 2004.