University of Kent

Simon Tollington
E-mail: st262

CV

My PhD focuses on immune function within the endangered Mauritian echo parakeet (Psittacula eques) and how this is associated with levels of inbreeding at the individual scale. 

Once the rarest parrot in the world, the Mauritius echo parakeet now boasts a population of around 340 having recovered from less than 20 individuals in the 1980s. Thanks to over a decade of intensive management it was the only species to be downgraded in the 2007 IUCN annual review from ‘critically endangered’ and is now classed as ‘endangered’.

Over 80% of this population are ringed and are therefore individually identifiable providing detailed information on pedigree which is supported by DNA evidence. Genetic information has also highlighted considerable variation in levels of inbreeding between individuals leading to a reduction in genetic diversity potentially reducing the ability of this small population to mount an effective immune response to disease.

In addition to the historic reasons for the decline in this species, such as habitat loss, competition for resources from introduced non-native species and threats from non-native predators, the recent emergence of an introduced pathogen further threatens their survival. Psittacine Beak and Feather Disease (PBFD) has been visibly present in the population since 2004, it is a potential immunosuppressant and is thought to cause death as a result of secondary infections such as hepatitis.

Immunocompetence will be quantified for as many as 200 individuals and tests will be repeated to evaluate changes in immune function as infection progresses. Levels of immunocompetence will be monitored across breeding and non-breeding seasons and will provide an estimate of heritability of immune response.

Individual inbreeding coefficients will be correlated with levels of immune response in order to identify any interactions and the non-native ‘out-bred’ populations of ringneck parakeet (P. Krameri) will provide a control.

Individuals will be tested by one or more of the following methods;

• PHA – Phytohaemagglutination assays have been used to quantify cellular level immune response in birds and involve injecting an individual with PHA and measuring the subsequent swelling of the skin at the site of injection.
• HHA – Hemolysis-haemagglutination assays are a relatively recent test for characterising immunocompetence and involve extracting plasma from whole blood samples and quantifying the interaction between natural antibodies and antigens by agglutination.
• Differential/total leukocyte counts – Blood smears will be taken and leukocyte counts performed on these smears in order to ascertain total white blood cell count and heterophil/lymphocyte ratios.

The results of this research will provide invaluable incite to the future successful management and further recovery of echo parakeets and endangered populations of birds worldwide.

Research is carried out in conjunction with The Mauritian Wildlife Foundation and The National Parks and Conservation Service (Mauritius).

Funding is provided by the Natural Environment Research Council as a CASE studentship supported by Wildlife Vets International. 

Simon's work was recently featured on the BBC.