E A N H S BULLETI N A publication of the East African Natural History Society, Box 44486, Nairobi, Kenya. Price 10 shillings. i?X r / ' If^ ? i'- ’< ^ -Z i S C; Co ■sl T-‘ . Xf €j ■ a 4 ■m SANHS BULLETIN NO^/ENBER/DECEMBER 1985 CONTENTS Dry Seaon Wildlife Dispersal in Masai Mara National Reserve ------ 71 Song Mimicry, Duetting and Anti phonal Song in African Birds ------ 75 The Occurence of Two Species of Double-collared Sunbirds in Nairobi -- - 78 Tree Frogs so Reviews - -- -- -- - - - 33 Tanzania Again ---------------------------- Ngorongoro Revisited Notice - -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - Shikra Predation on Uganda Wall Geckos ---------------- 90 Peregrine Striking Dove at Ngulia ------------------- gg Pied Kingfishers gj Owls Feeding on Termites ----------------------- Falcons and Eagles in Tsavo West National Park ------------ gj Brown House Snake - a Hearty Appetite ----------------- 92 Recent E.A.N.H.S. Camps ------------------------ 92 Birdwalk at xMuthaiga Golf Club, Nairobi. 8 August 1985 - -- -- -- - 93 New Members ------------------------------ 94 A Lament 94 DRY 3EAS0N WILDLIFE DISPERSAL RANGE IN MASAI MARA NATIONAL RESERVE, KENYA: OBSERVATIONS AND RESEARCH NEEDS Before tha land uses at the peripheral habitats of the Masai Mara National Reserve began to change, the Serengeti Migratory species entered Kenya both from within the reserve through the i.nternationa.l boundary with Tanzania and beyond to the Siana Plains in .the east. A>t the time of ray field observations, most individuals entered through the Sand River and the Mara River routes. Others entered from the strip between these two inuernal migration routes. Their movements in the reserve appecired to follow a systematic pattern. On entering the Mara Re^>erve from Tantaiiia, the migratory herds split. From the Sand River m.igration route, the larger groups usually go through Keekorok Lodge and Posee .Plaiixs to the Talek River. On crossing the river they move on to the Governor's camp area in the north which they occupy for most of their stay in the reserve. Small splinter groups, rather than travelling straight on to the Governor's camp area, move eastwards to Olairautia, traversing the Olemelepo gate area, Talek and Posee Plains to the Governor's camp locality. From the Mara River route, movements are made straight on through the Meta Plains across the Talek River towards Governor's camp. Minor splinter groups traverse other areas before converging on the ncrthor.Iy Governor ' s camp area. When forage becomes depleted in the Governor’s camp area, the built-up migratory populations move on to the \/est through the Kichv/a Tembo grasslands and woodlands , across the upper reaches of the Mara River (v^ithin the reserve) , to the Serena Lodge area. They graze on while movements continue to the Oloololo gate in the northwest, back through the same Mara Triangle to the lower reaches of the Mara Rivez' in Kenya. The migrants cross tne Mara River at the Kenya- Tanzania border to Serengeti National Park. Their return journey to the Serengeti is largely through the Mara River route. ^''Tiiile occupying the reserve, Wildebeeste Connvchaetes taiirinus and Thomson's Gazelle Gazella thomsonii are observed to return to grazed areas where or a mii’xg stimulated grass regrowth was available. The Loita Plains wildebeeste mi-jratory group v/hich returned to the Governor's Ccimp area at the time of Lhe Serengeti migrants peak occupancy, remain after their return to the Serengeti National Park . EFFECTS OP MIGRANT OCCUPAI^GY ON TEE RESIDENT HE-IBIVORES WII’H SPECIAL REFERENCE TO THE BUFFAiO HERDS Many distinct br.ffaio herds, some of over 2C0 iiidi^mduals , utilized the high- lands, plains, woodlands ar.d slopes in the reserve. The buffalo herds were seen in areas ranging from the Mara'Ttr'r.pie in the west through Posee Plains, Talek Olemelepo, Keekorok to Olaimuti.a sectio.ns of the reser^/c. I monitored the foraging activities of one herd (hereafter referred to as the Ngama buffalo herd) observed to maintain a grazing circuit between the Ng.ama Hills, the slopes and lowland r3,r-ge sites before the Serengeti migrants entered the reserve about 10 July, 1082. Aparc from tours undertaken between 1980 and December 1981 from Nairobi, the autho.r spent the period from December 1981 to November 1982 in the Masai Mara Wildlife Research Station, near the Olemelepo Gate. In the day time, the Ngama buf.fe;los grazed the slopes and the highland woodland thickets. A.t sunset, they descended, from the highlands to the lowland areas where they used both tha water and grazing resources including the lawns of the premises of the Wildlife Research Scation. Tlxis circuit cf grazing move- ments from lowland range sites (evenings and na ghr. time) to slopes and high- land woodland thickets during the dr.'^g became a routine for the Ngama buffalo herd before the arrival of the Serenget.i. migrants. Beginning in , when the migrants occupied the reserve, the Ngama buffalo herd no longer used their total v/et seaoca range. They apparently depended more on the higblo.:.:! thickets and slope ranges for their food. The decrease in 71 iCiQORiEN 7ildebeoste and buffalo. He has further suggested a food resource limitation for the Serengeti migratory herbi- vores. Stelfox et al . (1980) ho.ve estimated buffalo population in the Mara region as 25 000 while Sinclair (1974) j>ut the mean crude density of buffaloes in the Masai Mara National Reserve at 9.0 individuals per km^ . Onyeanusi (1983) observed that both the migratory Idebaeste and the resident large herbivores dispersed to the lives tocl: gracing areas outside rhe reserve boundaries at the peak of the Serengeti migrants occ'.’puncy of the Mara Reserve. Localised food resource shortage was reported, and it would seem that the movements of large herbivores beyond the Mara Rese:' ve boundaries mighc be stimulated by the added competitive effects of the migrants, part;^cularly the wildebeeste (Table 1). On the other hand, both the Serengeti migi ant wildlife species and the resident wildlife competed with the domestic livas'cock at the peripheral ranches. RESEARCT NEEDS hND SUGGESTIONS Large herbivore carrying capacity in Ihe Masai Mara National Reserve requires a long-term multi-discrplina.:<'Rr research programme. On a large scale, the Kenya Rangeland Ecological Mcnitcring Unit is doing a lot to monitor the animal population dynamics range condition and treads etc. On a small scale, a lot still remains to be done in the Mara Ressrva particularly in the areas of the migrant population dynamics, herbaceous and woody plant productivity in the dry season in order to gain knov7 ledge of the dry season large herbivore carrying capacity. ilncther area that equally requires urgent research is the effects of migrant occuparxcy on the resident v'ildlife and livestock species populations. A modest beginning could h'e made v;ith rhe buffalo populations. A.R.E. Sinclair was extending his research on popjulat.Lon dynai..lcs, including buffalo, to the Mara Reserve in 1981 and 'Rrh; g-’DubJ.rn la Ph.D. scudent) started her investigations involving woodland dvnsmics in fne sane vcar. My short term studies on the Mara grassl.and productivicy and utilization (approx. oiiC year) still requires further investigation, t'ildlifa msn ngemicn f , per se, be.i n.j essentially a management of habitat/range suggest.^ that 3 arm: i:mall--scale herbivore carrying capacity investigation is critical in che 'Laru Reserve, uonsidsrinq the increasing migrant populations, iiicreasing T:erl_rher'i I lar,c.--'ase and ever chenging seasonality of the Mara region. REFERENCES McNaughton, S.O". (1975) oursnaoti migratory viidefceeste: facilitation of energy flow by grazing. S'-cieure J91; 92-94. Onyeanusi, A.E. (19C3) The prcdi.cmion and fate of grasslands in Masai Mara National Reserve, Kenya, Uxu'ublished M.Gc, Theses, University of Nairobi, Sinclair, h.E.E. (197^^) The natural rt c;ulatio’'s of buffalo population in East Africa: .IV , The food s'pply as a requlatJ.ng factor, and competition. East Africcia Wildlife Jc arnal 12: 291-311. Stelfox, J.G., Peden, D.G.. Mbuguc., S.^h, Amuyunsu, C.L. and Hudson R.J. '(1980) Population, stoc];.ing rates and distributions of wildlife and livestock on Mara and Loita Plai.ns ■: Decenhar 1978 - November 1979. KREMU Technical Report Series No, l9. Zrugustine Egwu Onyeanusi*- • f ' ...Irar.-dtq' ct f'rirbbi, Kenya. *Present Address; Forestry search Iiistitute of N'geria, Federal School of i';il-dlifo 24ana semen t, Irivate Mail Bag 268, New Bussa, KVai-"c. Rts.ta , i.'-!i.geri a. 73 Average Wildlife Occupancy (No./km^) from eight study sites within the reserve, and livestock occupancy at the peripheral Talek area during the dry season (July - October) . 1— • H- » l-» K vn CO CO CO CD ft) 00 00 00 -u U) OJ o cn ft) g o w CO s CO 3 0 H- c+ o p- •< 3 3 CD 'Z 3 CD 3 O H p) n 3 t M H) c h-‘ 3 ' — £U O cQ pj C H- X 3" p- CO W rt o H- e 0 G , — , rt 3 ftl t) > n > CD pj ft) 4 CO jo M cn • * • • • M * s S CO s *3 CO CO fu M CD CU pj pi CD CD ft cn O K CD I-! n H n H- OJ 0 (D h| pj 3 CD CD p 0 p- cn 3 P- 3 3 TO 3 k: iQ PJ X) ^ cQ cO > P) S cn CO M (D 0 CD CD t-- 0) rt rt 3 ct (t o CD H- O P- UJ. H' o t) fu 3 \ 0 o 3 (D S C 3 H- 2: cq fu 3 p) n ft) rt ct pj * P) ■ — • p) P- cn o rt 0 cn P- p p- 0 P) P> 3 H- 3 'w' Oi cn S S' H CD t> I — * 1-^ PI o 00 'O O O o o to CP Ot o o o o o o o 3^ (— » a tx) M w CO ft] CO 1 « o o o cn tl rn * O L*'J O ft) o § 00 C3 Q H O cn 3 to M cn on 0 Pi u> to OJ o 1 o o o o o o 3 p* •< Hi CO 3 O P< 0 ft) w CO ft) o ■T ft) G . > 1-3 H f o to Pt 2 (O < CO Nil ft) oi u> 1 O o 1 CO O o CTi o 74 TABLE SONG MIMICRY, DUETTING AND ANTIPHONAL SONG IN AFRICAN BIRDS One of the special delights of living in distant places is learning entirely new plants and animals, particularly new birds and their songs. This is a challenge because many look and sound confusingly alike, at least at first. Sometimes this is because we are not yet familiar with the new songs we hear, but it is also that world-wide birds in similar habitats have evolved similar songs. Some of this may be accounted for by the fact that all songbirds are capable to some extent of mimicry including mimicking other birds and some bird families have developed this to a high degree, such as the New World family Mimidae, which includes cat- birds , thrashers and mocking-birds . Birds from different families and orders that have existed sympatrically over long periods of time have evolved certain song patterns that are quite .similar . For instance, there are singing styles that characterize the songs of birds of open grasslands. Many have fricative buzzy sounds suggesting those of insects, while others have been described as having tinJcling sounds and squeaking songs, and still others have loud and clear whistles. Contrasted to this, the songs of many woodlajjd jbiirds including tropical species are often rich and melodic, being described as flute-like and bell-like and even organ-like. Dr Charles Hartshorne, the University of Texas octogenarian professor of philosophy and ornithologist, has much to say on this subject in his book Born to Sing. This difference (to our ears anyway) of song quality may be partly explained by the fact that grass- land species belong largely to faniilies not famous as singers - fringillids, emberiziids, ploceids, larks and. pipits (though among these- are some outstanding exceptions) . Woodland birds include more families with exceptional singers - thrushes, chats, solitaires, bulbuls, mimids , bush shrikes, etc. It is note- worthy that while tropical shrikes, starlings and even some kingfishers such as the Woodland Kingfisher have developed remcirkable songs, outside the tropics these birds are not known for their singing abilities. What is mimicry in birds? A precise determination of what is and what is not mimicry is very difficult. Closely related birds (e.g. American House Finches, Purple Finches and Cassin's Finches) may sing very much alike, but this is not considered to be mimicry (or is it?) . Sometimes two unrelated species of birds sound very much alike to us. Is bird A mimicking bird B or the other way around, or perhaps it is only our interpretation of a similarity of the songs that leads us to believe that mimicry exists. For example, to our ears a noisy flock of Ruppell's Long-tailed Glossy Starlings flying overhead sounds much like a flock of squeaky parrots at times and has fooled us more than once. The Northern Olive Thrush Turdus abyssinicus occurs in East Africa, It looks and sounds very much like an American thrush the American Robin T, migrator ius. Both are thrushes in the same genus , so even though widely separated they might be expected to have similar songs. In Uganda, a more common thrush is the African Thrush T. pelios a paler edition of both the Olive Thrush and the American Robin. t^That is most interesting is that it has an entirely different song. The Olive Thrush has a chirrupy song much like the American Robin, whereas the African Thrush has a loud song consisting of short phrases repeated three or four times, then changes to another phrase, again repeated, continuing this way for many minutes. These sustained outbursts of song remind an American listener of a Mockingbird, so much so that it would be easy to believe they were somehow related, or at least had at some time in the remote past been associated with one another. Recently, we got a letter from a couple who had not been in East Africa a month. They wrote that "one of our pleasures is hearing the mockingbird, just like back home" - obviously they were hearing the African Thrush. The Mockingbird belongs to a purely New World family, Mimidae, which includes catbirds and thrashers, also famous mimics. What seems to be true mimicry is widespread among African birds. Williams (1980) lists the following outstanding examples - Anteator Chat, Morning Thrush, Robin Chat, Red-capped Robin Chat, Snowy-headed Robin Chat, White-browed Robin 75 list Chat, R;;;!.'"':" Ch'Rtorer, ;;r:po.l ■;C^;'hlar and Gtarlir'a. 71 ',t brl-.d can be greatly expanded. Several species of starlings are laxmics^ (as is the introduced Corrmon Starling in Inerica). Williams mentions additional mimics that are not listed here. Outside the tropics it i.s usually only the males that sing loudly sustained songs, pres urn cibly to attract females and estalDlish territories. There are rare exceptions. In Southern California we have heard female Black-'headed Grosbeaks Pheuticus malahocephalus sing beautifully, both on and off tna nest. Warbling Vireos sing, from, the nest occaslonaJ ly , but these m.ay be males as it is difficult to distinguish sex in vireos . In the tropics borh male and female birds sing equally wgjI, especially in East Africa. They may 3i,ng separ7cd Coucal CentropuB supercil- locus has a song or call (the distinction aa tween a song and a call is ^ague; technically the order Cuculifcriues aren't classified as songbirds) that resembles the sound made by water bubbling out of a large bottle as it is poured onto the ground. The vernacular name cf this bird is "Water -bottle Ej.rd'- . In early morn- ing before daybreak this bird renders an eerie but lovely song-call in response to other caucals calling in the. distance as \:'ell as to respond to the call of its mate, fc:mriing antipdionul duets, trios and even choruses as one bird after another ans.wers the calls of the preceding bi'*d. They begin quietly, dipping slightly in pitch, then ,rising joack to ‘“he original pitch and tippii,!g over at the end, producing a sound scicewhat .tike '’bioo“>-looo-lcoo-looo-looo-looo-looo" that is carried on by a secerd bi.rd a.nd uhen ptssed on tc still another bird and another . The Aif rican Bush Shrikes , family .Malaco'notidaa , are famous for their souvgs sung autiphonally and as duets. One is the Trepneal Bcafsou Lacicrius ferruglneus , jet-black above with a soft pearly'-pi.nk underside. ,A bird utters three or four lovely beJ.l-likc notes in rcoid succession followed. j.nmediate.ly by an answering loud "cc,:.A'ee'' f,rcm the mate, the o-ntirc song ceem.i.ng tr> be from a single bird unless the diffc.rent positions rare ncti.csd. The 'lose.‘ly related Elack-headed Gonolek L. barba?sus erythrepastez is c'.o‘. of che most attractive birds in Africa, jet-black above and bright blood- red. below. :^itez being utterly/ silent for many minutes it will suddenly make a Icud two note "KWEEOO'p- ’vvliicli is follov/ed instant- ly by the mate's ansv’ering ‘’CHUKRR'u The most rema.'-kable thing about these performances of bo+'h species is the uhiliu/ of. the second bJ.rd, to respond so in3tanta.neous].y to the call, of th.e first bird, Gevu.ral other kinds of bush shrikes also p.roduce uhcce nxitiphcnal explosions. Unquestionably the most beautiful and acco;;iplished African songbirds are the many species c ' th.niGhes k.nown as robin chats . The most coinon one in many Uganda gurdexio is the Wlii re -b.r cured Robin Chat Coesypha heugl..ni. Another superb singer is the Sxxovxy-headed Robin Chat C. rJ.velcapilla . These birds are exception- ally skillful m.lnics but they also sinq super.bj.^’- alone as V7ell as in breath-taking duets, filling the .m.r au dawn on’ duck with their farobJ >ir.q outbursts of tumultous song. TV'o White-browed Robin Chats will sit will begin with, a v/hisper-quiot ., "weeor- w'eeer, xiceerr" facir-.g each other and one gradually inorea.^ing in vol-ome to an ear -splitting ’hvH' sam.vO time the other bi.rd sings for awhile and this ma“/ chengo EEERR .. TvHEIbtERR , i’FBI'lEERR , loudly "DFAR DCRCTUy, DE/xR CO a.notho.i; thsmo, perhaps WIJEEEERR" v/hile at the DCROTHY, DEIk DOROTHY" tc •'DCCKALEESE, DOCkALEEE , 76 DOCI