Abundance, Distribution, and Threats of Grey Parrots in Nigeria

Description

This dataset, collected in 2018/19, presents information on the abundance, distribution, and threats to African Grey Parrots in Nigeria. We provide details on the locations and types of habitats where African Grey Parrots have been recently sighted. The distance of each habitat to the nearest mangrove, an important breeding site for the parrots, is also included. The habitats are grouped under the following categories: Cross River Forest Area (CRFA), Niger Delta Creek (NDC), Western Forest Area (WFA), and Lower North-East Forest Area (LNEFA). Information on encounter rates of the parrots across the two seasons—rainy and dry—was provided, along with the seasonal variations in abundance and perceived threats as reported by community members living near the forest sites where the surveys were conducted. In addition to the perceived threats, we provided information on onsite observations of the threats, including trapping of adult individuals, nest poaching of juveniles, logging, and hunting, to reveal the spatial variations of these threats.

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Line Transect Surveys were conducted at most sites, with the exception of Abigborodo and Andoni Island, while Questionnaire Surveys were conducted at all but four sites. A total of 228 local residents were interviewed. Interviews focused on individuals knowledgeable about the habitat and parrots, such as hunters, trappers, and farmers, who had long-term familiarity with the forest areas. The surveys were conducted during both the breeding (dry) and non-breeding (wet) seasons between 2018 and 2019. Some sites could not be accessed during the wet season due to weather conditions and security concerns. Observational Field Surveys involved walking two transects per site, each approximately 5 km long, at a speed of 1-2 km per hour during early morning hours when African Grey Parrots are most active. A total of 331.5 survey hours covering 160 km were completed. Observers recorded data on parrot group size, behavior (feeding, flying, etc.), location, and habitat type. In addition to visual sightings, parrots were detected through their vocalizations. Three parrot roosting sites were also identified, and population counts were conducted at these sites with the assistance of park rangers and community members. Abundance and Population Trends Encounter rates, calculated based on the number of parrot groups detected per survey hour, were used to estimate relative density at each site. Parrots were observed in low numbers at some sites, making it difficult to apply standard distance methods for estimating population density. Instead, a simpler method was used, assigning each site into one of three categories: Absent, Low Density (0–1.5 groups/hour), and High Density (>1.5 groups/hour). Additionally, a semi-quantitative assessment of population trends over the past 20 years was derived from local residents' perceptions. They were asked whether parrot populations had increased, decreased, or remained the same. These insights helped estimate population trends, complementing the observational data. Seasonal Abundance Patterns To understand seasonal variation in parrot abundance, interviewees were asked to indicate when they most frequently encountered parrots. Their responses were categorized as "more in wet season," "more in dry season," or "no seasonal change." These findings provided an understanding of how parrot populations fluctuate between the breeding and non-breeding seasons. Habitat Analysis The study also measured the distance of each site to the nearest mangrove forest, using GIS tools and data from the World Atlas of Mangroves. Mangroves are known to be important breeding sites for African Grey Parrots, and proximity to these areas may influence parrot abundance and distribution.

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