Cygnus olor – Alarch Dof – Breeding resident
Comparison with previous atlas:
| 1984-88 | 2003-07 | |
| Breeding confirmed | 8 | 13 |
| Breeding probable | 1 | 6 |
| Breeding possible | 2 | 4 |
| No of tetrads occupied | 11 (of 478) | 23 (of 490) |
| Percentage of tetrads | 2.3% | 4.7% |
Largely introduced into Pembrokeshire to grace ornamental waters, the mute swan has now become naturalised. Habitat requirement is for a supply of aquatic plants, sufficient room to be able to take off and a suitable bank or reed bed in which to place its bulky nest. Formerly nesting on saltings, this practice had ceased by the time of the 1984-88 survey. During the 2003-07 survey they had reoccupied this niche at Cosheston Pill, the Haroldston region of the Western Cleddau and the tidal upper limit of the Eastern Cleddau. Otherwise all nests were found on fresh waters.
Ten pairs were breeding in the county during the 1984-88 survey, 22 breeding pairs were found during the 2003-07 survey. The increase was accompanied by an expansion in distribution to the east and an increase in the number of pairs in the south of the county, particularly at Pembroke Mill Ponds.
Rees, et al. 2008, Atlas of Breeding Birds in Pembrokeshire 2003-07. Pembrokeshire Bird Group.
