An Ecological and Molecular Study of the European Nightjar (Caprimulgus Europaeus) and Its Allies
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An ecological and molecular study of the European nightjar (Caprimulgus europaeus) and its allies Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor of Philosophy Carl Thomas Larsen May 2017 1 1 Acknowledgements Firstly, I would like to thank my primary supervisor Mike Speed for all of his good advice, good humour and relentless support throughout my PhD. I am also grateful to other members of my supervisory team, primarily Michael Berenbrink (University of Liverpool) for his guidance and also Rosanna Cousins (Liverpool Hope University) and the friendship of other PhD students at both the University of Nottingham and the University of Liverpool. Special thanks go to Paul Barwick (Nottinghamshire) and Mark Warne (Dorset) of the Forestry Commission for support during fieldwork, and Ian Alexander of Natural England and especially Brian Cresswell of Biotrack for practical advice during fieldwork and their invaluable experience and knowledge of working with nightjars. For four summers between May 1994 and August 1997, Sherwood Pines Forest Park became my second home, and during the summer of 1998, it was Wareham Forest, and I will always be grateful to the institutions and countless people who helped to make me feel so welcome. Chris Bray provided a home, friendship and challenging mountain bike routes in Sherwood Pines and gladly tolerated my nocturnal behaviour. The project would not have been possible without the skills and fieldwork of members of the Birklands Ringing Group (BRG) (Nottinghamshire) and the Stour Ringing Group (SRG) (Dorset). In particular, special thanks go to Phil Palmer and Ian Smith (BRG) and Brian Cresswell (SRG) for devoting so much effort into catching birds and finding nests. Various members, too numerous to mention, of both ringing groups and volunteers from the Forestry Commission and the Wildlife Trusts also helped with fieldwork including nest finding and radio tracking. I am also indebted to the ‘Bird lab’ at the University of Nottingham where I completed much of the molecular work and in particular, Nick Harvey for advice on wet work, both in the lab and at the pub. I would like to thank David Parkin for support with laboratory and fieldwork and in particular with blood sample collection. I would also like to thank Harry 1 Noyes in the School of Life Sciences, University of Liverpool, for advice and help with DNA sequence analysis. Over the course of this thesis numerous people have kindly made available their observations or unpublished data or provided samples for DNA analysis. For their generous help, I warmly thank Clive Barlow, Mark Brigham, Rob Clay, Nigel Cleere, Des Jackson, Johan Ingles, Phil Palmer, David Pearson, Rob Pople, John Stoner, Till Topher and Chris Woods. I am also very grateful to Tony Parker at the World Museum Liverpool, Mark Adams at the Natural History Museum Tring and Henry McGhie at Manchester Museum, for their kind assistance during my work with specimens. For my interest in birds, and nature more generally, I would like to thank my dad for the stories of the people and wildlife he encountered on his global travels as a boatswain on merchant ships and my art teacher, Ken Houghton, who took me birding most weekends from the age of 11 and taught me so much. Finally, my long suffering partner Lucy, who by her own admission, has little interest in birds, but who provided the necessary ‘child-free’ space in which to complete the thesis, deserves the greatest recognition. Thanks Lu. My children, Ella, Lola and Elijah had to cope with my absences during fieldwork and my moods when the lab work didn’t work. Thanks and sorry kids. This PhD was funded by a Liverpool Hope University Vice Chancellor’s Lectureship. Additional financial support for the project was provided by the Forestry Commission and Biotrack donated radio transmitters and tracking equipment and considerable unpaid labour during the Dorset fieldwork in the form of Brian Cresswell, who has become a friend for life. 2 Carl Larsen AN ECOLOGICAL AND MOLECULAR STUDY OF THE EUROPEAN NIGHTJAR, (CAPRIMULGUS EUROPAEUS) AND ITS ALLIES Abstract 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 3 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. 4 Contents AN ECOLOGICAL AND MOLECULAR STUDY OF THE EUROPEAN NIGHTJAR, (CAPRIMULGUS EUROPAEUS) AND ITS ALLIES ......................................................................................................... 3 Abstract ......................................................................................................................................... 3 Contents…………………………………………………………………………………………………………………………………………5 List of Tables ................................................................................................................................ 12 List of Figures .............................................................................................................................. 13 List of Appendices ....................................................................................................................... 15 CHAPTER ONE .............................................................................................................................