Methodology

Literature Survey

Although there is some historical data on Minziro and the surrounding areas, ornithological literature is restricted to recent surveys by Baker and Hirslund (1984), Baker (1987, unpublished), Baker & Baker (1993) and Moyer (1999). The birds of the Sango Bay Forests, which includes Malabigambo, were described for the first time by Friedmann & Williams in 1969 and data on the Sango Bay area has since been compiled by Matthews (Davenport & Howard 1996). Standard texts on the region’s avifauna were used throughout.

Field Methodology

·         Observation

General observations were carried out at all times. Observations were also carried out in different areas within the forest habitat, as well as in the surrounding woodland and grassland. Species were identified by sight and by call; the latter being especially the case for nocturnal birds and some of the more inconspicuous passerines.

·         Mist netting

Mist netting allows for the sampling of less conspicuous species which inhabit the ground and shrub layer. As mist netting only samples to 2m above ground, this method is useful in surveying birds of lower strata. The number of mist nets used (thus effort) reflected what it was considered both practical to monitor and what it is considered requirement to provide an accurate assessment of the forest reserve. All birds caught were fitted with a standard Museum of Nairobi rings and measurements taken. These measurements include; tarsus, wing, bill, tail length and weight. This data along with moult data is stored by the Tanzanian Ringing Scheme and allows monitoring of both species and individual birds if they are re-caught at a later date.

Data Analysis

Species lists

All species lists are compiled in taxonomic order following Dowsett and Dowsett-Lamaire (1993) and given a Tanzanian number (Tz No) following Baker & Baker (2000). In addition, some species are assigned an ecological type, as follows;

Forest-dependent specialists (FF) are species that are dependent on the forest for either all or part of their life cycle. This includes the availability of food and suitable nesting sites. Not only are these species dependent on the forest, their abundance and populations can be greatly altered by disturbance within the forest or the area surrounding it.

Forest edge (Fe) are species which are commonly found on the forest edge and may rely on the forest for nest sites, food or protection.

Forest-non dependent (Fn) are species that are often recorded in forests, although not dependent on the forest habitat for breeding. However, it may be likely that the removal of the forest would directly or indirectly alter species populations. Some forest-non dependent species may be dependent on forest edge for seasonal movement or feeding.

Species of Special Interest

The species of special interest are those birds which are either; Only recorded for Tanzania at Minziro, many of which many are biome-restricted. Birds which were ringed in greater, or lesser numbers than expected and re-traps from 1987. Were recorded by observation in numbers greater or lesser than expected, or other notable behaviour. Recorded sightings of either of the two globally threatened species known to occur.