APLORI has two core functions. One is capacity building for conservation biology in West Africa, and the second is to facilitate fundamental biological research based in West Africa. Relatively little ecological field research is carried out in West Africa because of lack of infrastructure and logistical difficulties. APLORI aims to help address these issues by providing a well-run field station where it is possible to carry out research relatively easily in a tropical savannah environment. To date APLORI has been host to many research projects that need a West African base. These pages give an idea of some of the research that APLORI has been involved with: sometimes we have just provided accommodation and logistical support for outside projects, whereas for others we have provided core trained personnel and expertise or the projects have originated as part of APLORI’s functioning as a research and training institute. The APLORI related research detailed here is by no means complete but gives an indication of what we do, and we can do in the future.
Below is an outline of some main areas of research and on the right are specific details organised by the principal investigators and topic.
The ringing program neatly encapsulates both of the core functions of APLORI: providing training opportunities and research opportunities. We have been ringing birds at APLORI and elsewhere in Nigeria since the start of 2001 and have been running a constant effort mist netting site at the Institute site since 2002. By 2012 we had trapped over 25,000 birds of 368 species and of these we had recaught 7,300. Many birds have also been individually colour-ringed providing a resource for behavioural ecological studies around the Institute. Much of the data from this program is basic ornithological data but these are lacking for many West African bird species. For example, the ringing guide on this site provides much new data on the identification, sexing, ageing and biometrics of many species.
The data from these ringing studies feeds into a number of research programs:
- Life history of tropical savannah birds:
- Survival estimates
- Timing and patterns of moult
- Timing and duration of breeding
- Mass variation
- Palearctic migrant studies
- Residency and survival of over-wintering Palearctic migrants
- Migration phenology
- Body condition
- Intra-African migration
- Patterns of residency in African “resident” species
- Population dynamics
- Breeding output
- Population monitoring
APLORI has been a base for studies into the density and distribution of Palearctic migrant birds wintering in West Africa since its start. Up until the last few years there has been almost no research done into the ecology and occurrence of the one third of “European” bird species that spend the winter in West Africa or that use West Africa as a significant staging area during their migration. For example, there may be hundreds of papers on common whitethroats based on studies in Europe, but there are only a handful that have studied whitethroats in Africa. And this is despite whitethroats being the iconic catastrophic declining migrant because of factors unknown operating on their wintering ground: over the winter of 1968-69 half of the UK population of 5 million whitethroats disappeared. Since then their numbers have gradually climbed back, but we can only guess at the reasons for the original decline and the changes in numbers since then. And meanwhile other iconic species such as turtle doves, nightingales, cuckoos and spotted flycatchers have declined by up to 80% in some Western European populations. It is likely that each migrant species has its own specific ecological problems because of habitat and climate change somewhere and at some time during its migration and wintering period. Each species must therefore be studied during the wintering period in Africa and APLORI is able to do this.
- Distribution of Palearctic migrants in the Sahel
- Temporal and spatial variation in migrant density
- Migration stop overs and fattening rates
- Habitat associations
- The effects of deforestation on densities of migrants
- Occurrence of migrants on farmlands
- Residency and itinerancy during the wintering period
- Age and population differences in residency patterns
Threatened and endemic species
Two of the four bird species endemic to Nigeria, the rock firefinch and the Jos Plateau indigo bird, occur around APLORI. The rock firefinch has been extensively studied at APLORI and the rarer and elusive indigo bird, which is a brood parasite on the rock firefinch, remains to be studied.
Another Nigerian endemic, the Ibadan Malimbe, has also been extensively studied by APLORI personnel. Recently the distinctive and isolated race of the red-capped larkCalandrella cinerea that occurs near APLORI has been under genetic investigation to determine whether the form merits full species status.
Two endemic bird areas partly occur in Nigeria, the Cameroon Highlands and the Cameroon and Gabon lowlands. About 21 species of restricted range are found in them of which 8 are species of global conservation concern: APLORI led survey work and research projects have targeted grey-necked picathartes Picathartes oreas, white-throated mountain babbler Kupeornis gilberti, green-breasted bush-shrike Malaconotus gladiator and Bannerman’s weaver Ploceus bannermani.
APLORI has contributed its expertise to monitoring the risk from avian influenza. An avian influenza surveillance programme was carried out at various sites in Nigeria where there were reports of avian influenza in 2007 with support from the Global Avian Influenza Network for Surveillance (GAINS)as part of the United nation’s Food and Agricultural Organisation (FAO) avian influenza programme coordinated by Wetlands International.
The main objective was to gather pharyngeal (or tracheal) and cloacal samples of wild birds in order to determine the presence of HPAI H5N1. A waterbird monitoring programme was carried also out at Hadejia-Nguru wetlands and Lake Chad. The main objective of this programme was to establish sites with large concentrations of waterbirds that may have the potential to spread the HPAI H5N1. A satellite tracking programme to determine waterbird movements, especially in relation to the potential role that they may play in the transmission of avian diseases, such as avian influenza was carried out at Dagona Waterfowl sanctuary. Satellite transmitters were fitted on 9 garganey, 6 comb ducks and 2 white-faced whistling ducks. Substantial movements were recorded within Africa, and in the case of garganey, into Europe.
In 2008 another survey was carried out to find out if cases of avian influenza were still present. Three samples showed to be positive for AI, all three from fresh droppings of Spur-winged Goose. A final survey in 2009 was carried out as a follow up on the last two projects to determine if avian influenza was still present. No samples were found to be positive for AI.
The behavioural ecology of tropical birds
APLORI has provided the base for a number of behavioural-ecological studies. APLORI provides opportunities to mark individual birds and the surrounding environment is suitable for observational and field-experimental studies. Tropical savannah birds are relatively unstudied compared to temperate species, yet research in tropical birds has the potential to greatly increase our understanding of behavioural ecology. This is particularly true for life history, competition, predation and body condition.
Life history theory explains why some animals live a long time and have few offspring while others might only live a short time but have many offspring. Such trade-offs are usually a consequence of environmental variation. For example temperate birds that have to face difficult winter conditions with a low chance of survival are more likely to invest in larger clutches and more offspring so at least some survive. In contrast tropical birds have more uniform and equable conditions during the year and so often have a high chance of survival: selection can therefore promote the option of adult birds looking after themselves and producing fewer and more well cared for offspring. Consequently we tend to see large clutches and lower survival in temperate regions compared to the tropics. Work at APLORI has examined this theory in detail and has shown in general that such life history generalisations are true. Nevertheless there are many exceptions and there is a strong pattern of seasonality operating in tropical savannahs which creates its own life history trade-offs at this scale.
Competition is likely to be the dominant force governing population dynamics in tropical areas because populations are likely to be at their carrying capacity, lacking the periodic severe environmental conditions of temperate areas which may keep populations level low. But how tropical birds compete for resources, how this varies seasonally and how competition might structure the high diversity we find in tropical areas has yet to be explored. Recent projects have examined the dynamics of foraging granivores (firefinches, waxbills and weavers for example) at artificial patches to examine how important competition (and in some cases facilitation through flocking reducing predation risk) is in determining density and distribution. Research has also identified the importance of seasonal availability of water and suggested how travel time to the last remaining water sources in the dry season may limit foraging.
Predation is another major issue which has been well studied outside of the tropics, but remains largely unstudied within tropical savannahs. How predation risk affects distribution and density of birds through its “non-lethal” effects (i.e. a bird avoids an area to reduce its risk of being attacked) has been studied extensively using giving-up density experiments. In these experiments the amount of food taken from a patch gives an idea of the risk an animal will take to forage in a particular area: safe areas are depleted fully but risky areas can only be fed in if there is some sort of equivalent high gain. Direct effects of predation are also being examined. These appear to be small except with respect to predation on eggs and chicks.
Body condition studies at APLORI have been carried out for the last ten years in conjunction with the ringing program. Mass variation in temperate birds has been shown to indicate not only fitness and individual survival, but also to act as an index of environmental conditions and potentially population dynamics. These theories are being extended to the tropical birds at APLORI and initial findings suggest that savannah systems are much better than temperate systems in elucidating the details. For example, in tropical areas there is no harsh winter period so birds can maintain low mass when not breeding (they do not need fat as insurance against long cold winter nights or snow cover preventing foraging). This means that other more subtle determinants of mass variation can be observed more easily in tropical birds, such as an interrupted foraging response increasing mass during breeding. Recent work has confirmed the close relationship between life history and body condition and the seasonality of the environment (wet and dry seasons in APLORI’s case). Further work is exploring the relationship between environmental quality and measures of body mass.