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E-Thesis 252 views 43 downloads

The breeding ecology and habitat utilization of some freshwater marsh passerines / Derek Thomas

Swansea University Author: Derek Thomas

DOI (Published version): 10.23889/SUthesis.60185

Abstract

The breeding biology of the Reed Warbler Acrocephalus scirpaceus and the Reed Bunting Emberisa schoeniclus was studied at Oxwich Marsh, Gower, primarily during the summers of 1978 and 1879. Three marshland habitat types were identified, and the utilisation, feeding ecology and breeding success of bo...

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Published: Swansea 1981
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa60185
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Abstract: The breeding biology of the Reed Warbler Acrocephalus scirpaceus and the Reed Bunting Emberisa schoeniclus was studied at Oxwich Marsh, Gower, primarily during the summers of 1978 and 1879. Three marshland habitat types were identified, and the utilisation, feeding ecology and breeding success of both species in respect of these habitats was considered. In 'pure reed marshes' both species bred earlier, produced heavier young, were predated less and had higher nesting success (i.e. probability of a nest producing young) than those breeding in 'mixed marshes' and other areas. Invertebrates were collected in each habitat. Diptera accounted for a very high proportion of all potential prey items throughout the breeding season. Pure reed marshes produced more invertebrates than elsewhere, and overall peak abundance measured by numbers and biomass ocurred from mid-June to mid-July, coinciding with the time when most young of both species were in the nest. The diet of nestlings based on faecal analysis and hide observations showed Reed Warblers to be generalist feeders, with a similar diet in all habitats. Reed Buntings proved to be more specialist feeders, with a diet varying considerably between habitat types. Adults of both species foraged mostly in carr when nesting in pure reed marshes, whilst those from mixed marsh nests mostly utilized the marsh. Habitat selection in the Sedge Warbler Acrocephalus schoenobaenus was studied. A separate habitat classification was used, which indicated a preference for nesting in areas with a mixed dense vegetation matrix, consisting mostly of reed and bramble. These areas contained the highest densities of breeding pairs and were occupied first. Evidence was given to support the view that the plant species content within a breeding territory was less important than its vegetative complexity, which was measured and shown to be negatively correlated with settlement time.
College: Faculty of Science and Engineering

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