Details

Autor(en) / Beteiligte

• Bonnington, Colin
• Smith, Damian

Titel

Do bridge construction activities influence birds using the River Mersey, in northwest England?

Ist Teil von

• Bird study, 2018-07, Vol.65 (3), p.346-356

Ort / Verlag

Thetford: Taylor & Francis

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Capsule: Bridge construction works over a major river did not adversely impact the overall wintering and breeding bird assemblage, although contrasting species-specific trends in breeding number were noted. Aims: To determine whether the wintering water-bird and breeding bird assemblage using the River Mersey, in northwest England, was influenced by bridge construction works. Methods: Common bird census and wintering bird surveys were carried out before and during construction of the Mersey Gateway bridge. The species abundance and richness of wintering water-birds, assigned to a group ('Waterfowl', 'Wader', 'Wetland species' and 'Gull') and breeding birds, assigned to a group ('Salt marsh species', 'Waterfowl species', 'Wader species', 'Warbler species' and 'Other passerine species'), were separately compared before and during the works. Results: We found little evidence that the bridge construction displaced wintering water-birds and instead found that for most bird groups, their assemblages were higher during the construction works, compared to before. Similarly, we found no evidence that the bridge construction reduced breeding density of any bird group. Contrasting species-specific trends were, however, noted, with some species only recorded breeding during the construction works, and other species recorded in higher breeding densities before the works. Conclusion: The inadvertent increase in the mud-flats around the bridge structure since the works resulted in more mud-flat being exposed for a greater amount of time, and thus increased the foraging opportunities for many birds. This may at least partly explain why overall wintering bird abundance and richness increased since the works began. Although most breeding birds either increased or remained stable, in number since the works, a small number reduced. This may have been a consequence of the removal of suitable nesting habitat. This study provides a preliminary assessment of the influence of bridge construction on birds.