Features

Rock Pipits in Christchurch Harbour

February 2008

Between 15th and 18th February 2008, visits were made to Stanpit Marsh and Hengistbury Head with the specific intention of photographing Rock Pipits. The main purpose of the exercise was to try and draw exact comparisons between birds believed to be of the Scandinavian race littoralis and those of the resident British race petrosus .

A degree of supposition, based on habitat, was applied to determine the likely race of individual birds prior to them being scrutinised in detail. For example, petrosus birds are resident on the Hengistbury Head shoreline and cliffs, where they breed. Other than the appearance of juveniles, there is no significant fluctuation in numbers throughout the year, suggesting the population is largely resident. Conversely, the mainly freshwater marshes of Stanpit only harbour Rock Pipits during the winter months and, historically, it is these areas where classic spring individuals appear from March onwards. Taking these factors into consideration, the current thinking is that many, if not all, the birds on Stanpit are littoralis type, whereas the Hengistbury individuals are likely to be exclusively petrosus .

The photographs below were taken within four days of each other using the same camera with identical settings. Further, any subsequent digital processing was consistent across all images and the actual light conditions in the field were extremely similar.

Plate 1: 15th February, Central Marsh, Stanpit - presumed littoralis - Mark Andrews

When compared to Plate 2 (presumed petrosus ), note:

• the paler, greyer upperpart colouration.
• stronger and broader supercilium, particularly behind the eye.
• apparently paler outer tail feathers.

Plate 2: 18th February, Hengistbury Head presumed petrosus - Mark Andrews

When compared to Plate 1 (presumed littoralis ), note:

• the darker, olivey upperpart colouration.
• weaker supercilium.
• apparently darker outer tail feathers.

The following plates provide additional images of birds from both sites. Further points of interest may be:

• there is a suggestion that the dark upperpart streaking on a littoralis appears to contrast more with the background colour. In particular, see Plate 6. This is presumably a function of the overall paler colour of such birds.
• the shape and extent of the breast streaking does not seem to vary noticeably across the birds.
• the bare part colouration seems consistent in all these photographs. However, observations of birds not photograhed here suggest that the lower mandible in particular can vary from black to pale yellow/pink, but this seems to be the case on both races.

Plate 3: 15th February, Central Marsh, Stanpit - presumed littoralis - Mark Andrews

Plate 4: 15th February, Central Marsh, Stanpit - presumed littoralis - Mark Andrews

Plate 5: 15th February, Central Marsh, Stanpit - presumed littoralis - Mark Andrews

Plate 6: 15th February, Central Marsh, Stanpit - presumed littoralis , but different
individual to Plates 3 to 5. - Mark Andrews

Plate 7: 18th February, Hengistbury Head - presumed petrosus - Mark Andrews

Plate 8: 18th February, Hengistbury Head - presumed petrosus - Mark Andrews

The points raised in this article are merely those observed by the authors, who would welcome feedback of any kind.

David Taylor & Mark Andrews