Raptor Road Survey of Northern Kenya 2–15 May 2016
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Raptor Road Survey of northern Kenya 2–15 May 2016 Darcy Ogada, Martin Odino, Peter Wairasho and Benson Mugambi 1 Summary Given the rapid development of northern Kenya and the number of large-scale infrastructure projects that are planned for this region, we undertook a two-week road survey to document raptors in this little-studied region. A team of four observers recorded all raptors seen during road transects over 2356 km in the areas of eastern Lake Turkana, Illeret, Huri Hills, Forolle, Moyale, Marsabit and Laisamis. Given how little is known about the biodiversity in this region we also recorded observations of large mammals, reptiles and non-raptorial birds. Our surveys were conducted immediately after one of the heaviest rainy periods in this region in recent memory. We recorded 770 raptors for an average of 33 raptors/100 km. We recorded 31 species, which included two Palaearctic migrants, Black Kite (Milvus migrans) and Montagu’s Harrier, despite our survey falling outside of the typical migratory period. The most abundant raptors were Rüppell’s Vultures followed by Eastern Pale Chanting Goshawk, Hooded Vulture and Yellow-billed Kite (M. migrans parasitus). Two species expected to be seen, but that were not recorded were White-headed Vulture and Secretarybird. In general, vultures were seen throughout the region. The most important areas for raptors were Marsabit National Park, followed by the area from Huri Hills to Forolle and the area south of Marsabit Town reaching to Ololokwe. There was a surprising dearth of large mammals, particularly in Sibiloi and Marsabit National parks, which likely has implications for raptor populations. Sibiloi National Park was nearly devoid of all wildlife including raptors, particularly the southern half, and livestock was seen throughout the park. Based on similar surveys done annually elsewhere in Kenya, this region in the far north remains very important for raptors, particularly vultures. 2 Introduction Across the arid landscapes of northern Kenya, birds of prey, or raptors, are the most ubiquitous group of predators and scavengers. Both charismatic and intrinsically valuable, raptors also deliver broad benefits to ecosystems as well as to economies from the benefits of tourism. Raptors control prey populations and facilitate carcass decomposition, as well as act as indicators of areas of high biodiversity because they are sensitive to human disturbance that may impact many different species across whole communities. Kenya has 67 species of both diurnal and nocturnal raptors; the vast northern region harbors species that do not occur elsewhere in the country and it is Kenya’s last stronghold for rare and threatened species such as White-headed and Egyptian vultures. Currently 19% of raptor species found in northern Kenya are threatened or near threatened according to the IUCN Red List. For example, pan-African populations of eight species of vultures have plummeted by an average of 62% over the past 30 years, while iconic raptors such as Bateleur, Secretarybird, and Martial Eagle can rarely be seen outside of Kenya’s protected areas. Kenya’s once vast natural landscapes have become overpopulated by humans and their livestock, or have been converted for farming, thus eliminating the prey base and nesting sites for raptors. Although northern Kenya remains the most undeveloped area of the country, there has been a recent rush to exploit the region’s natural resources (e.g. wind power and oil) and to use the area as a transport corridor for oil pipelines between northern Kenya and neighbouring countries. Of particular relevance to birds is the development of two high voltage power lines, each of which will bisect this vast region and pose a significant threat in the form of collisions and electrocutions to large avian species, including raptors, bustards, cranes, storks and pelicans. The largest wind farm in sub-Saharan Africa is currently under construction just south of Lake Turkana, which may impact both local and migrant populations of birds and bats. A large dam under construction in southern Ethiopia along the only inlet supplying water to Lake Turkana is severely threatening the regions’ communities, livelihoods and the wildlife that all depend on this vitally important water resource. Already, northern Kenya is suffering from unprecendented levels of habitat degradation and loss of biodiversity. As a result of burgeoning human and livestock populations, the grasslands in this region are severely overgrazed, woodlands have been heavily exploited for charcoal production, and conflict between wildlife and local residents has greatly increased. The result is rangelands with impoverished biodiversity that are less resilient to climatic changes and provide fewer ecosystem services, and where attitudes toward wildlife have become increasingly intolerant. Given that northern Kenya has never been systematically surveyed for raptors and that there are numerous large-scale development projects ongoing and planned for this region, we undertook a two-week raptor road survey in order to gather baseline data on numbers and 3 diversity of raptors, as well as opportunistically surveying large mammals and other biodiversity of this little-studied region. Methods Our team consisted of six people and two vehicles. Team members and their roles were as follows: Lead vehicle: Martin Odino- surveyor Darcy Ogada- surveyor Peter Wairasho- surveyor and data recorder Ben Mugambi- driver and surveyor Trailing vehicle: George Karumbo- driver Safo Ogom- security Our team of surveyors has worked together counting raptors on annual 5-day surveys since 2013. The team counted all raptors seen while the vehicle was moving. The vehicle often stopped to ensure correct identification of raptors, including taking photographs for all species whose identification was not immediately obvious. Immediately obvious species were typically Augur Buzzard, Pale Chanting Goshawk, Black-shouldered Kite, and Long-crested Eagle. Occasionally, raptors seen while the vehicle was stopped were also included if it was believed that these individuals would have been observed if the vehicle was moving, otherwise they were recorded as incidental species and geo-referenced for purposes of distribution mapping only. We stopped and counted vultures (using a spotting scope) at one accessible breeding cliff. We also recorded all opportunistic sightings of raptors seen outside of counting times, these included raptors seen at our campsites and especially owls, which were heard, but rarely seen at night. All the above-mentioned sightings were recorded for purposes of distribution mapping, but were not included in our analyses for this report, except where mentioned. We divided our route into 29 sections based either on transects that we had delineated on previous surveys (from Thika to Ololokwe) or where there were logical ending points, such as where roads came to a junction or ended at a park gate. Each section averaged 74 km. The aim was not to repeat sections, but due to the limited road network this was unavoidable for some sections. Four sections totaling 370 km were repeated twice. For purposes of this report, all raptors observed on repeated sections are included. 4 Figure 1. Map of the survey route. The lower red marker indicates Thika where the survey began and the red marker above it indicates Nanyuki where the survey ended. The survey was undertaken in a clockwise direction. The area highlighted in red indicates sections that were counted twice. Yellow stars indicate locations where we spent the night. Vehicles traveled between 50–80 km/hr on major highways (i.e. tarmacked roads) and more slowly on murram and unimproved roads where the condition of the road dictated driving speeds. The main highway to Moyale is now completely tarmacked apart from a small section around Marsabit. Tarmac roads accounted for 49% of all roads, with murram and unimproved roads accounting for 51% of all roads. We camped at park campgrounds, private campsites, and one night we camped outside the Anti-Stock Theft camp in Gaas. The only places where we did not camp were in Huri Hills and Forolle where we stayed in a guest house and in Illeret where we were kindly hosted at Turkana Basin Institute. 5 All raptor records will be submitted to the African Raptor Databank, http://www.habitatinfo.com/african-raptor-databank/. For most of the route, we also opportunistically logged all bird sightings via the app for the Kenya Bird Map Project http://kenyabirdmap.adu.org.za/. We also recorded the locations of large mammals as their numbers were surprisingly few. Records of reptiles will be submitted to the Kenya Reptile Atlas http://www.kenyareptileatlas.com/. Results We began our survey at Thika (-1.02, 37.07) on 2 May 2016 and completed it in Nanyuki (0.02, 37.09) on 15 May (Fig. 1). We surveyed a total of 87 hrs and 59 mins over 14 days, which included one full day off (for the drivers), and two half days, one for vehicle repairs and the final day ended at noon. On average, we began our surveys at 0920 and ended at 1735. We aimed to begin surveys by 0800, but we were often delayed by side trips to obtain fuel, minor vehicle repairs, or the time required to return to the point where we closed the previous evening. The surveys were conducted immediately after one of the heaviest rainy periods in recent memory. Only brief light rains were encountered on the first day, after which no further rain was encountered. We were unable to traverse the Chalbi desert due to the recent rains that left the area flooded for at least one month, according to the locals. We recorded 770 individual raptors over 2356 km for an average of 33 individuals/100 km. The highest number of raptors/km was found in Marsabit National Park, followed by the area from Huri Hills to Forolle, and the area south of Marsabit Town reaching Ololokwe.