This thesis covers two broad areas of investigation; the conservation ecology of the European nightjar (Caprimulgus europaeus) nesting in lowland pine plantations in Eastern and Southern England and the application of phylogenetic methods to the Caprimulgidae. The nightjar has become a popular study organism with many studies involving the use of mist netting and attachment of GPS tags. However the effects of such close contact and potentially high degree of disturbance has not been studied systematically. The ecological work aimed to determine the effects of capture, instrumentation and blood sampling on breeding nightjars and also habitat selection for nesting and the importance of disturbance induced predation using artificial nests. Mist netting, telemetry and blood sampling had no effect on breeding success and no measurable long terms effects on philopatry or survival. Mist netting resulted in 0.75% mortality. Radio tagging caused short term reduction in activity and minor feather wear. Blood sampling caused temporary weight loss in bled chicks. We recommend that feathers are used instead of blood for DNA analysis. Telemetry showed that song territories (territory used primarily for nesting) of mated and unmated males were similar and nightjars shared airspace above territories so census workers should factor this into surveys. Male nightjars established territories on clearfell, plantations less than 10 years old and heathland but avoided plantations when the canopy has closed. Territory size varied by habitat (mean range 4.6ha to 9.3ha) but all territories had a compactness ratio (circularity) greater than 0.64 (where 1 = perfect circle). Nightjars located their nests adjacent to soft edges (broad transition of vegetation of similar height) and chose vegetation of intermediate density requiring a balance between nest concealment and vigilance. Artificial nests were created on habitat used by nightjars and baited with quail and plasticine eggs. Depredation was similar to nightjar nests however predation of nightjar and quail nests was mainly avian, whereas plasticine eggs were predated by mammals. These findings recommend future studies should avoid using plasticine eggs and use cameras to record predation events. Depredation was higher on clearfells and lowest in 4-9 year plantations and heathlands. Success of artificial nests on bracken dominated clearfells and < 4 year plantations increased when visited. Depredation was higher and more rapid in large territories and when adjacent to hard edges but lower and less rapid with higher vegetation density and territory compactness. The implications of this study are that controlled disturbance does not increase nest predation but that both real and artificial nest survival is dependent on optimal vegetation cover. These results have important implications for habitat conservation initiatives for this species nesting in commercial pine plantations. In the phylogeny work, cytochrome b was used as a probe. Bayesian analysis found that within the Caprimulgidae there were four geographically isolated clades with bootstrap support greater than 70%. Phylogeny suggests that the genus Caprimulgus is not monophyletic and is restricted to Africa and Eurasia and that Caprimulgus species from outside this area have been misclassified as a consequence of retention of primitive adaptations for crepuscular/nocturnal living. Future studies should use a more slowly evolving gene and include more taxa. The phylogeny was used to investigate the ecological correlates of bristle variation. Functional bristles were absent in the majority of the nighthawks and varied in the remaining two New World nightjar radiations and the Old World radiation. The length, number and stiffness of facial bristles on museum specimens of the Caprimulgiformes were measured A phylogenetically controlled comparative analysis suggested that rictal bristles have a mechanical role in protecting delicate head structures in general (habitat used for nesting) and foraging habitats. Complex foraging habitats selected for longer, more flexible rictal bristles that might have improved mechanoreception while such bristles were shorter in semi-open foraging habitats and vestigial in open habitats. Bristles are primitive and have become vestigial multiple times within this Order. These events are associated with habitat shifts leading to changes in foraging behaviour and selection on bristle characteristics, which in turn may have led to speciation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:724483 |
| Date | January 2016 |
| Creators | Larsen, C. |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/3008131/ |
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