Friday, 21 March 2014

Searching for Grey Parrots in Ghana

Posted by Nathaniel Annorbah & Stuart Marsden

In his study, Nat has to cover a huge study area of
60,000 sq. km across the South West of the country.

The aim of the PhD research is to assess the historic and current distribution, abundance and ecology of the Grey Parrot Psittacus erithacus in Ghana in order to make informed predictions about the sustainability of trade and land-use changes. Relevant data on other frugivorous birds such as hornbills and pigeons are being collected at the same time. Despite its large geographical distribution, the Grey Parrot population is suspected to be suffering a rapid decline because the extent of the annual harvest for international trade, and the high rate of ongoing habitat loss. The species is listed as Vulnerable in the (BirdLife International 2014).

Nat has already conducted surveys for Grey Parrots and other fruit-eating birds between April 2012 and March 2013, and he is now again in Ghana to continue his work on greys. His study area is huge - about 60,000 sq. km, comprising a mosaic of inhabited, cultivated and forested areas in south-western Ghana, the stronghold of grey parrots in the country.

Selective logging in forest reserves takes the largest trees. Logging company staff tell us that the huge trees they harvest often have 'nail ladders' allowing trappers to climb to the parrot nests (Photo: Stuart Marsden).

The study area was partitioned into a grid of 10 x 10 sq. km cells. A random sample of around 50 cells has been selected for surveys. 3-5 days are spent in each cell trying to find evidence for the presence of parrots and other frugivores. These ‘presence’ points will form the basis of a MAXENT analysis of current parrot distribution. Interviews were also conducted in the cells to obtain information about local people’s knowledge of the Grey Parrot, but also to record the socio-economic aspects of the its trade. Particularly important is the information on the historic presence of grey parrots in each cell – these points will form the ‘historic’ presence points for a MAXENT analysis of the past distribution.

Nat interviews local hunter-farmers to better understand the historic range of the Grey Parrot in SW Ghana (Photo: Stuart Marsden)

A great part of fieldwork was to locate roosts of Grey Parrots and to count birds to estimate roost population sizes. G. Dändliker (1992), a CITES consultant, did a survey of parrot roosts in Ghana in the early 1990s – some of these roosts contained hundreds of birds. It is our aim to visit as many of these roosts as possible to see how they have changed over in the subsequent 20 years. Locating roosts needs accurate information provided by trappers or local knowledge in general and a lot of legwork.

Fieldwork conditions: rain can soon transform roads in rivers (Photo: Nat Annorbah).

Fieldwork in Ghana has not been easy. Torrential rain makes ‘road’ conditions atrocious, the 4WD has taken a battering, electricity is scarce, and illnesses such as malaria are a real concern. Even local elections made things difficult in places.

A total of just 101 parrots were encountered during the first year’s survey. Parrots were recorded in just nine of the 31 surveyed sites surveyed  and not one wild grey parrot has so far been recorded in this year’s survey. Grey Parrots were present in only three of twelve roost sites revisited from the 1992 study and all 16 of Dändliker’s roosts visited so far this year have been ‘empty’. We will soon post on what looks like a collapse of the grey parrot population right across the country.

Excessive parrot trade has surely had a big hand in the disappearance of Grey Parrots from Ghana. Despite being incredibly rare in the wild, a few can still be found for sale.


BirdLife International. 2014. Species factsheet: Psittacus erithacus. Downloaded from on 14/02/2014.

Dändliker, G. 1992. The Grey Parrot in Ghana: a population survey, a contribution to the biology of the species, a study of its commercial exploitation and management recommendations. A report on CITES Project S-30.  Unpublished report to CITES.

Nat's PhD is funded by

Monday, 10 March 2014

Our Conservation, Evolution and Behaviour (CEB) Research Group launched

Posted by Stuart Marsden

Our new research group based in the School of Science & the Environment at Manchester Metropolitan University has just been launched (see With it comes what we hope will be an attractive and informative website introducing staff and their research interests, research students and their projects, news and activities, and links to teaching.  The CEB group website is in progress at It is worth a look, if only for the lovely photos.

(Photos. Top: Michele Menegon; Mid: Stuart Marsden; Bottom: Paul Donald)

The CEB group

Much of the conservation research we do focuses on biodiverse regions of the world. We are active across Africa, Southeast Asia and South America, working on birds, mammals, amphibians and other groups in tropical forests and other ecosystems. We also work closer to home, in British habitats on habitat fragmentation, restoration of salt marshes, impact of wind farms and noise pollution. We have a special interest in capacity building in developing countries both through PhD training, and taught MScs.

(Photos. Top: Paul Higginbottom; Mid and Bottom: Stuart Marsden)

An understanding of ecology, evolution and behaviour provides important insights and new perspectives on the science of conservation. Our group is interested in a wide variety of evolutionary and behavioural topics that range from bioacoustics and determinants of primate social structure to whale behaviour and bumble bee foraging. We also use theoretical models (such as random forest analyses) to assess extinction risks, and DNA sequence analyses to monitor gene flow and minimal viable population size. Our research ranges from the applied (GPS collar tracking of working Police dogs) to the more fundamental (behavioural neuroscience of rodent whiskers).

(Photos. Top: Michele Menegon; Mid: Christian Devenish; Bottom: Paul Donald)
There are around 15 permanent staff in the group. Information about the research interests of individual members of staff can be found within their staff webpages at As is stressed in the MMU news piece, we see the group as more than just research. We all teach and supervise Masters students, and see the group as a focal point for our wider activities. For example, we have a thriving taught master’s programme with courses in Animal Behaviour, Conservation Biology, Countryside Management, Biological Recording, Conservation Genetics and Bird Conservation.

(Photos. Top: Michele Menegon; Mid: Stuart Marsden; Bottom: Paul Donald)

Saturday, 1 March 2014

Eyeing up the age structure of grey parrot populations

Posted by Filippo Marolla and Simon Valle

Filippo Marolla is a biology student from the Sapienza University of Rome. He's working with Simon to test some new methods for estimating densities and age ratio of Grey Parrots in Príncipe.

Among the several objectives we have set for our second fieldwork season in Príncipe, is a test of a non-invasive method for the estimation of the age ratio of the population of Grey Parrots. Determining the proportions of age classes in an animal population is crucial to the understanding of its dynamics and viability. However, this operation can be complicated for species which are hard to age in the field. To date, the only reliable method available to age Grey Parrots is the colour of the iris (Dändliker 1992). 

Downy chick with completely black iris (photo Filippo Marolla)

Captive fully fledged 'grey-eyed' juvenile grey parrot
 on Príncipe (Photo: Filippo Marolla)

When the chicks first open their eyes (about 7-10 days after hatching), the iris is black. During the first year, it slowly turns paler, passing through different shades of grey, and after the first year, it gradually turns bright yellow. Dändliker (1992) reckons that individuals can be aged up to four years of age, but, due to the variability among individuals, the only reliable separation is between first-year birds and others. Using this aging criterion can be quite easy for birds in captivity, but it can be a real nightmare in the wild, as parrots are either very difficult to approach when perched, or they typically fly high and fast in closed canopy forest.

Our objective is to test if photographs especially taken from strategic lookouts can be used as a method of estimating juvenile/non-juvenile ratio in Príncipe. We will take high-definition pictures of as many parrot individuals as we can, whether they are flying or foraging, using a Canon Eos 700D camera with a Zoom Lens EF 100-400mm (f/4.5-5.6). We are currently carrying out a training period in order to identify logistic problems and to improve our skills in taking good photos as quickly as needed. So far results are encouraging and, despite many ups and downs, the number of usable photos (i.e. where the iris colour is clearly recognizable) increases from session to session.

Three parrots flying over São Joaquim are readily identifiable as adults 
(Photo: Filippo Marolla)

Parrots often use preferential flyways to move daily in small flocks from foraging areas to roosting sites. We are focusing our efforts on some open areas located along these flight paths. Oque Daniel and El Miradouro are two elevated lookout points, located respectively in the North-West and in the East side of Príncipe, from where it's easy to spot parrots flying over, often right above your head. Other observation points, e.g. the surroundings of São Joaquim, are located in feeding sites such as flat areas with high densities of oil palms Elaeis guineensis, which give us the chance of taking pictures of perched birds. A typical working session consists in two hours of photo-catching during the time of the day in which parrots are most active, i.e. between 6 and 8 AM or between 4 PM and the sunset at 6 PM. 

View from El Miradouro, one of the strategic lookouts from which photos of flying grey parrots are taken in Príncipe (Photo: Simon Valle)

After some weeks of work, we are now able to provide some figures about how things are going.  In the best session in El Miradouro, we photo-catched 71 flying individual parrots on about 150 sighted, among which 25 have clearly recognizable iris colour, i.e. an aging success rate of 17.5%.

A grey parrot flying over shows the bright yellow eye typical of an adult
 (Photo: Filippo Marolla)

In the best session in São Joaquim, we photo-caught 22 perched individual parrots on about 43 sighted, with 10 individuals with clearly recognizable iris colour, i.e. an ageing success rate of 23%. Considering the practical difficulties associated with the method, we can be satisfied with the ageing rate we reached so far. 

 A perched adult feasting on the pollen from on Erythrina variegata  flowers 
 (Photo: Filippo Marolla) 

The first results are encouraging, suggesting that this kind of ‘photo-trapping’ might be useful for the study of grey parrot populations elsewhere in their vast range. Our next step is to see if we can detect changes in population structure across months using repeat photographic surveys. We expect the juvenile/non juvenile ratio to be at its maximum in March-April – when juveniles have just fledged – and at its minimum in August-September – when juvenile mortality has taken its toll. 

Two adults flying in a oil palm plantation in São Joaquim (Photo: Filippo Marolla)

This distant bird flying away is still readily identifiable as an adult 
(Photo: Stuart Marsden)


Dändliker, G. (1992). The Grey Parrot in Ghana: A population survey, a contribution to the biology of the species, a study of its commercial exploitation and management recommendations. A report on CITES Project S-30. Unpublished report to CITES.

The research on the Grey Parrots in Príncipe is funded by 

and supported by