Breeding Biology of the Southern Grey-Headed Sparrow in the Namib-Naukluft Park, Namibia P.A

July 2003 Bird Numbers 12 (1) Breeding biology of the Southern Grey-headed Sparrow in the Namib-Naukluft Park, Namibia P.A. Bridgeford NamibRand Nature Reserve, PO Box 43, Maltahöhe, Namibia The Southern Grey-headed Sparrow Passer a similar trend in choice of nest site. Only diffusus is widely distributed in southern two were in natural sites, namely a wood- Africa, except in southwestern Namibia and pecker nest and a hole in the broken end of southwestern Western Cape Province of a branch. Southern Grey-headed Sparrows South Africa (Craig 1997). Despite it being used the Zais nest in the asbestos chimney so common, little is known of its breeding for over 20 years. The nests were filled with biology. Maclean (1993) stated that incuba- feathers, but a few pieces of paper and cloth tion and fledging periods are unrecorded, were also found. Indeed, most nests were so while Tarboton (2001) said that incubation is filled with feathers that it was difficult to see not recorded and nestling/fledging period is eggs or chicks. c.19 days. This paper gives some new infor- mation on the breeding biology of this spe- Breeding season cies in Namibia, based on Southern Grey- Breeding seasons are slightly later in Na- headed Sparrows monitored at Zais (24°01'S, mibia than elsewhere and coincide with rela- 16°09'E) in the Namib-Naukluft Park from tively late summer rains. This study, with 17 1986 to 1993. records, showed January (24% of all active The study area, below the escarpment in nests), February (29%), and March (24%) as the pro-Namib, is in a semi-desert and the peak breeding months at Zais (Table 1). savanna transition zone (Giess 1971). How- The summer rainfall, which generally starts ever, as Zais is situated next to the Tsondab in January, is highest in February/March River, the area is mainly Acacia woodland (Table 2). For Namibia as a whole, the peak- dominated by A. tortilis. The majority of the breeding season was also February (28%) breeding records were from nests in the gar- and March (28%), but extended from Janu- den. Where possible, the nests were checked ary through to May (Table 1). It is interest- visually or by inserting a hand into the nest. ing to note that four of the 100 records for They were monitored as regularly as possi- Namibia are from the Hoesch and Nietham- ble, but most observations were interrupted mer expedition in 1933/34. Tarboton (2001) by official duties away from home. Some gave the breeding season as mainly Novem- eggs were removed from easily accessible ber–March throughout southern Africa. nests and measured with vernier callipers. Although many birds were examined Egg size and clutch size while ringing, no sexual dimorphism could Clutches were 3–4 eggs (mean 3.3 eggs) at be determined. Some ringed birds were sexed Zais (Table 3). This corresponds with clutch after they were seen mating. sizes in Maclean (1993) and Tarboton (2001). Five eggs were measured: range Nest sites 18.2–19.4 mm × 14.2–14.4 mm (mean All the nests at Zais were in man-made struc- 18.9 mm × 14.28 mm). This differs only tures, such as an unused asbestos chimney, marginally from the 19.2 mm × 14.3 mm nest boxes, wall cavities, and the chassis of given by Maclean (1993) and Tarboton a wrecked vehicle. Nest record cards from (2001). Eggs were grey/brown and heavily the Ornithological Section, Ministry of En- blotched with dark brown. vironment and Tourism in Windhoek, show 31 Bird Numbers 12 (1) July 2003 Table 1. Breeding season of Southern Grey-headed Sparrows in Namibia. Number of nests with eggs or chicks N Nov. Dec. Jan. Feb. Mar. Apr. May Zais 17 1 0 4 5 4 1 2 Whole of Namibia 100 1 4 9 28 29 19 10 Total 117 2 4 13 33 33 20 12 Incubation To determine who was incubating at night, I put up a net around the entrance be- Only eight records of incubation period were fore first light and only the colour-ringed obtained; these were 11–14 days (mean 12.5 female emerged. This was the only time I did days). Incubation for the congeneric Cape this. More observations are needed to deter- Sparrow P. melanurus and House Sparrow P. mine with certainty which parent incubates at domesticus is 12–14 days (Maclean 1993; night. Of the other three Passer species in Tarboton 2001). southern Africa, Maclean (1993) stated that In this study, it was found from colour- both male and female incubate, and in the ringed birds that the male and female both Cape Sparrow, the female incubates at night. incubate during the day. Possibly because breeding is in the hottest months of the year, Nestling and post-nestling period the one regularly observed nest was fre- The nestling period was 16–19 days (N = 5; quently left unattended by both adults. At mean 17 days). This is identical to that re- 14:00 on 6 April 1886, at the chimney nest, corded for both Cape and House Sparrows six days after commencing incubation, the (Tarboton 2001). Of all the observations of ambient temperature was 30°C, while the breeding Southern Grey-headed Sparrows, temperature in the nest was 32°C. Both only three records of the post-nestling period adults were in and out of the nest during this are considered to be of any value. These were time and on occasions left the nest for peri- 14, 17, and 21 days respectively. Both par- ods of 3, 7, 10 and 11 minutes. Both birds sat ents fed the chicks, but the female fed more on the edge of the nest with beaks open and often. wings slightly spread after emerging from the nest. Summary The breeding biology of the Southern Grey- headed Sparrow was studied in the Namib- Table 2. Total monthly rainfall in millimetres at Naukluft Park, Namibia, and new infor- Zais 1986–1993. mation gathered on various life-history variables. The majority of nests were in man- Nov. Dec. Jan. Feb. Mar. Apr. May made structures. The peak-breeding season was January–March, generally with 3–4 eggs 10.7 25.4 119.1 242.1 142.5 108.1 9.9 per clutch with both parents incubating. The incubation period was 11–14 days and the nestling period 16–19 days. The post- Table 3. Clutch size of Southern Grey-headed nestling period was 14–21 days, with both Sparrow at Zais, Namibia. parents feeding the chicks. No. of eggs per clutch 2 3 4 5 Giess W. 1971. A preliminary vegetation map of No. of records 1 7 5 – S.W.A. Dinteria No. 4 S.W.A. Scientific 32 July 2003 Bird Numbers 12 (1) Society, Windhoek. Craig A.J.F.K. 1997. Southern Greyheaded Spar- Maclean G.L. 1993. Roberts’ birds of southern row Passer diffusus. In: Harrison J.A., Allan Africa. John Voelker Bird Book Fund, Cape D.G., Underhill L.G., Herremans M., Tree A.J., Town. Parker V. & Brown C.J. (eds). The atlas of Tarboton W. 2001. Nests and eggs of southern southern African birds.Vol.2. BirdLife South African birds. Struik, Cape Town. Africa, Johannesburg. o o o The 9th International Roseate Tern Workshop, Wexford, Ireland, April 2003 A.J. Tree ADU Research Associate, PO Box 211, Bathurst, 6166. [email protected] Memories, memories, memories . came gion of the mitochondrial genome in an at- flooding back when I returned to my home tempt to identify different populations (re- country, Ireland, after a break of more than sults for South Africa pending complemen- 40 years. Blackbirds, Robins, Dunnocks and tary material from the Atlantic becoming Wrens singing in the hedgerows, flights of available for comparison). Greenland White-fronted Geese passing For many years, estimates of world totals over, honking excitedly as orderly skeins of Roseate Tern were given at around 30 000 departed for their breeding grounds; daffo- pairs, but recent extensive coverage of the dils and primroses flowering everywhere, multitudes of islands around the Australian horse chestnuts and sycamores bursting into coastline has come up with some staggering leaf and draught Guinness in the pubs. And figures. A minimum estimate of 70 000 pairs believe it or not, no rain! Putting aside remi- there alone puts Australia into worldwide niscences, it was also great to meet people I perspective and helps to make that continent had known only through correspondence or the tern capital of the world. Thus, the world the literature. So why Ireland for this work- population is now estimated at about 85– shop? Well, the southeast of the country is 90 000 pairs. Although we have a mere 240 now home to the vast majority of Western pairs of Roseates in South Africa, it must be Europe’s Roseate Terns, hence the venue for remembered that these probably represent an the workshop. isolated population of unknown origin and Why are these Roseate Tern workshops therefore remain classified as Endangered. convened? In certain parts of the world, the The workshop was convened by Steve Roseate Tern is classified as Threatened and Newton and Oscar Merne, both from Eire. because of the deteriorating situation in the Oscar is a contemporary of mine, each north Atlantic, researchers from North known to the other, but we had never met. America, Western Europe and the Azores The gift of the gab, common to so many came together to discuss their problems and Irishmen, he certainly has and his knowledge find solutions.

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