ON THE BREEDING OF THE WHITE-RUMPED SWIFT (APUS CAFFER CAFFER) IN GATOOMA

Crawford, R. J. M., Cooper, J. &; Shelton, P. A. 1982. Distribution, population size, breeding and conservation of the Kelp Gull in southern Africa. Ostrich 53:164:177.

The Kelp Gull Lams dominicanus in Africa occurs coastally between Luanda, Angola and Delagoa Bay, Moçmbique. It breeds between Cape Cross Lagoon, South West Africa/Namibia and Riet River, eastern Cape, South Africa. Censuses of nests and breeding birds at all known southern African breeding localities in the period 1976–1981 indicated that 11 199 pairs bred at 52 localities; 79.5% of this population occurred in South Africa, 57,1% in the Saldanha Bay to Dassen Island region, southwestern Cape. Of the breeding pairs 83% occurred on offshore islands and rocks. Colony size at islands is related to their surface area andMayalso be influenced by food availability and the level of human disturbance. The species breeds in a wide variety of habitats ranging from cliffs and rock stacks to wooden platforms, lowlying vegetation among sand dunes and estuarine sandbars. Any available material is used in the construction of nests, whichMaybe as dense as 4/m² Clutch size is 2–3 eggs. In 1978 breeding took place earlier in South Africa than in South West Africa/Namibia. 92% of the population breeds m sites which are legally protected. Kelp Gulls have decreased or increased in numbers at some breeding localities but there is no clear overall trend. Any increases in colony size near urban areasMayresult in added airstrike hazards.     

Status and abundance of the African Black Oystercatcher Haematopus moquini at the eastern limit of its breeding range

From 1983 to 2004 the breeding population of African Black Oystercatchers along the East London coast has more than trebled. The population increase is probably due to immigration as local breeding success is low. There are three classes of birds: breeding pairs, tenants and visitors, and birds may change status during the breeding season. In the winter, birds aggregate into groups and some birds may disperse from the East London coast. The presence of African Black Oystercatchers in all months of the year shows that they are resident, but may only be resident in the general sense, and at a local level appear to be nomadic, wandering along the coast in search of resources and, in the summer, opportunities to breed. The birds remain at any locality only for as long as conditions are suitable, suggesting that the birds along the East London coast are mostly visitors that have dispersed from their natal areas in the south.     

DISTRIBUTION,POPULATION SIZE AND CONSERVATION OF THE SWIFT TERN STERNA BERGII IN SOUTHERN AFRICA

Cooper, J., Crawford, R. J. M., Suter, W. & Williams, A. J. 1990. Distribution, population size and conservation of the Swift Tern Sterna bergü in southern Africa. Ostrich 61: 56–65.

The Swift Tern Srerna bergü occurs commonly in coastal southern Africa, with a nonbreeding distribution extending the length of the southern African coast and into southern Angola. The known nonbreeding distribubon of the nominate subspecies S. b. bergü extends from Swakomund, Namibia to Kosi Bay, Natal, South Africa. In Natal its nonbreeding distribution overlaps with that of the subspecies S. b. enigma. The species very rarely occurs inland or far out to sea. The geedin distribution of tre nominate subspecies extends from Swakopmund to Algoa Bay, eastern Cape, South Afcnca.

Twenty-two breeding localities are known in southern Africa, but usually only six to seven are occupied. in any one year. Most breeding localities are marine islands where Swift Terns often breed in muted colonies with Hartlaub's Gulls Lorus hartloubii. In 1984 a complete breeding ansus estimated a breeding population of 4835 pairs. However, 6088 pairs were counted at only three localities in 1988. The size of the annual breeding population varies by a factor of as much as 1,6; although the overall size of the adult population is thought to be reasonably stable with no temporal trends evident. Thirteen breeding localities which are legally proclaimed nature reserves supported 72% of the 1984 breeding population. Existing and perceived threats to the Swift Tern are discussed in detail. To improve further tRe conservation status of the Swift Tern in southern Africa, it is recommended that: unprotected breeding localities be proclaimed reserves, also protecting those not on islands with adequate fences; feral cats be removed from breeding islands where they are present; and fisherman be educated to release entangled terns and not to discard lines and nets.     

Reproductive traits of marine terns (Sternidae): evidence for food limitation in the tropics?

Marine terns breed between 80°N and 70°S, making them a suitable group for examining links between latitude and reproductive traits. We investigated such traits for 34 taxa in seven genera, using analyses of residuals to correct for effects of e.g. female body mass and egg mass on other life history traits. Both tree- and K-means clustering, based on four traits excluding chick provisioning mode, identified two groups of terns—those that breed on tropical oceanic islands and those that breed along mainland coasts and at temperate islands (>40° from the Equator). Among mainland terns, there is a tendency for reduced clutch investment at low latitudes both between and within species. There is no interspecific latitudinal variation in incubation or fledging period of these terns, but intraspecific variation in fledging period (longer in the tropics) has been reported for one species. Tropical island terns, which mostly breed at sites lacking native ground predators, show extreme clutch reduction and lay a single, relatively large egg that has a long incubation period. Fledging periods are also long, despite the fact that these are the only terns to use multiple prey loading or regurgitation to feed their chicks. These patterns are interpreted as responses to low food availability stemming from a combination of low oceanic productivity, high bird densities because of breeding space limitation and localised prey depletion associated with central place foraging.     

FIELD STUDIES OF THE AFRICAN CRAKE CREX EGREGIA IN ZAMBIA AND KENYA

Taylor, P. B. 1985. Field studies of the African Crake Crex egregia in Zambia and Kenya. Ostrich 56: 170–185.

Field observations were made of a breeding population of African Crake Crex egregia at Ndola, Zambia from 1975 to 1980 and of a nonbreeding population at Mombasa, Kenya in 1981. Both populations are migratory and the Kenyan birds are thought to breed in southern Africa. Habitat requirements, migrations and patterns of occurrence are described. Population estimates give the density of breeding birds as 1 bird/2,6ha and of nonbreeding birds as 1 bird/1,99-2,73 ha. Local movements are evident at Mombasa. The crakes are thought to be territorial in both the breeding and nonbreeding seasons and the pair bond is sustained or formed during the nonbreeding season. Habits and behaviour are described, including courtship, copulation, aggression, feeding, roosting and vocalizations. Breeding, moult and predation are briefly discussed.     

6. REVIEWS AND CRITICISM OF NOMENCLATURAL CHANGES

CLARK, A. 1976. Observations on the breeding of whistling ducks in Southern Africa. Ostrich 41 59–64.

Records collected since 1954 show that Dendrocygna viduutu breeds in the Transvaal, Natal and Rhodesia, choosing for the most part a limited mid-summer period when most rains can be expected. D. bicolor records for the Transvaal and Natal show a similar pattern but in Rhodesia breeding is not so restricted. In the Transvaal and Natal most records were obtained near the more populated areas at man-made or artificial breeding grounds. Information is given on nest sites and construction, clutch and brood size, and the behaviour of nesting birds. The percentages of juveniles in flocks of D. viduuta following the breeding season are compared showing the apparent effect of rainfall on breeding success.     

FACTORS AFFECTING THE FOOD SUPPLY AND BREEDING SEASON OF RESIDENT BIRDS AND MOVEMENTS OF PALAEARCTIC MIGRANTS IN A TROPICAL AFRICAN SAVANNAH

The fact that Palaearctic migrants arrive in the northern tropical savannah of Africa during the dry season suggests potential competition for food with African species. Moreover, in the southern tropical savannah African species breed during the rainy seasons, when Palaearctic migrants are present. In the equatorial area of Serengeti, East Africa, an index of the food supply for insectivorous birds was obtained from 3 years of light-trap measurements and sweep net samples. Adults of Lepidoptera, Coleoptera, Orthoptera and Isoptera are sparse in the dry season but become locally abundant after the first rainstorms that mark its close. They are apparently blown by converging winds ahead of the inter-tropical front and settle to lay eggs where rain has fallen. These early storms therefore produce localized superabundances of food. In the ensuing rainy seasons insect abundance remains high. African insectivorous birds breed during the wet period, reaching a peak two months after the insect increase. It is suggested that this lag is due to the need to recover body condition, build up reserves for eggs, develop gonads and wait for vegetation and insect larvae to develop. In the samples available, breeding records of above-ground nesters peaked in the first rains, while ground-nesters peaked in the second (main) rains. Predators bred towards the end of the rains, when there is an abundance of fledglings and small mammals. Thus the food supply could act as the ultimate factor determining the timing of the breeding season in this area. Palaearctic migrants arrive in the Serengeti 4–10 weeks ahead of the main rain front. However, most species are only found where rain has fallen recently. When conditions dry up they move on to other wet areas. Thus they overlap with African species only where there is a superabundance of insects. When the rains become widespread Palaearctic migrants disperse into their usual habitats, and therefore appear not to compete for available resources with closely related species of African birds. The situation in West Africa, where residents and migrants overlap throughout the dry season, cannot be explained in the same terms.     

Genome‐wide population structure and admixture analysis reveals weak differentiation among Ugandan goat breeds

Uganda has a large population of goats, predominantly from indigenous breeds reared in diverse production systems, whose existence is threatened by crossbreeding with exotic Boer goats. Knowledge about the genetic characteristics and relationships among these Ugandan goat breeds and the potential admixture with Boer goats is still limited. Using a medium‐density single nucleotide polymorphism (SNP) panel, we assessed the genetic diversity, population structure and admixture in six goat breeds in Uganda: Boer, Karamojong, Kigezi, Mubende, Small East African and Sebei. All the animals had genotypes for about 46 105 SNPs after quality control. We found high proportions of polymorphic SNPs ranging from 0.885 (Kigezi) to 0.928 (Sebei). The overall mean observed (H_O) and expected (H_E) heterozygosity across breeds was 0.355 ± 0.147 and 0.384 ± 0.143 respectively. Principal components, genetic distances and admixture analyses revealed weak population sub‐structuring among the breeds. Principal components separated Kigezi and weakly Small East African from other indigenous goats. Sebei and Karamojong were tightly entangled together, whereas Mubende occupied a more central position with high admixture from all other local breeds. The Boer breed showed a unique cluster from the Ugandan indigenous goat breeds. The results reflect common ancestry but also some level of geographical differentiation. admixture and f₄ statistics revealed gene flow from Boer and varying levels of genetic admixture among the breeds. Generally, moderate to high levels of genetic variability were observed. Our findings provide useful insights into maintaining genetic diversity and designing appropriate breeding programs to exploit within‐breed diversity and heterozygote advantage in crossbreeding schemes.     

DISTRIBUTION,POPULATION SIZE AND CONSERVATION OF HARTLAUB'S GULL LARUS HARTLAUBIL

Williams, A. J., Steele, W. K., Cooper, J. & Crawford, R. J. M. 1990. Distribution, population size and conservation of Hartlaub's Gull Lorus hurtlaubii. Ostrich 61: 66–76.

Hartlaub's Gull Larus hartlaubii is endemic to southern Africa, where it breeds between Swakopmund, Namibia and Dyer Island, southwestern Cape Province, South Africa. The species has been re breeding at 48 localities within this range. Between 1984 and 1989 an estimated 12000 pain brered at 31 localities. Twenty-eet percent of the population breeds at Robben Island off the Cape Peninsula, sQuth Africa. Hartlaub's Gull frequently has low breeding success and is considered endangered in Narmbia, where 12% of the poulation occurs. However, the population is increaslng around the urbanmd Cape Peninsula where HartLub's Gull has the potential to become a pest species.     

Breeding distribution,population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa

Brooke, R.K., Allan, D.G., Cooper, J., Cyrus, D.P., Dean, W.R.J., Dyer, B.M., Martin, A.P. & Taylor, R.H. 1999. Breeding distribution, population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa. Ostrich 70 (3&4): 157–163.

The Greyheaded Gull Larus cirrocephalus occurs throughout southern Africa, both coastally and inland, and has bred at one time or another at 67 known localities since the 1860s. Most of these sites have been occupied by small numbers of birds, even single pairs, and for only one or a few years. The two principal breeding areas are the East Rand in Gauteng and Lake St Lucia in KwaZulu-Natal, both in South Africa. The next most important sites are Walvis Bay, Namibia and Lake Ngami, Botswana. The total southern African breeding population is estimated as about 2000 pairs. The Greyheaded Gull is not a threatened species in southern Africa, with 27 breeding sites supporting more than half the breeding population within formally conserved areas.     

DISTRIBUTION,POPULATION SIZE AND CONSERVATION OF THE CASPIAN TERN STERNA CASPIA IN SOUTHERN AFRICA

Cooper, J., Brooke, R.K., Cyrus, D.P., Martin, A.P., Taylor, R.H. & Williams, A.J. 1992. Distribution, population size and conservation of the Caspian Tern Sterna caspia in southern Africa. Ostrich 63: 58–67.

The Caspian Tern Sterna caspia occurs along the whole southern African coastline and on large river systems and water bodies away from the coast. A total of 28 definite breeding localities has been recorded in southern Africa. Breeding has occurred recently at at least 14 coastal localities between Swakopmund, Namibia, and Lake St Lucia, Natal, South Africa. Inland breeding has been recorded in recent years at Sua Pan, Botswana and Kalkfonteindam, Orange Free State, South Africa. Based on censuses conducted between 1980 and 1991, the southern African breeding population is estimated to be of the order of 500 pairs, 91% of which breed coastally and 89% breed on islands. Up to 290 pairs (58%) bred at Lake St Lucia. Seventyone per cent of the 1980–1991 breeding population falls within eight nature reserves. Conservation of the Caspian Tern in southern Africa requires protection at breeding localities, including commercial salt and soda ash extraction works, against the effects of changing water levels, human disturbance and predation. Pesticide levels of addled and abandoned eggs should be measured at selected breeding localities.     

Factors that affect fertility in a feral population of sheep

Feral livestock offer an excellent opportunity lo study factors affecting fertility as the physiology of their husbanded relatives is well known and social and environmental influences can be studied free of man's interference. This is so in the population of about 1250 sheep of the primitive Soay breed on the islands of St Kilda, Scotland. There is a high coincidence of oestrus amongst the ewes in mid November, and the breeding season is constant within a few days, from year to year. The breeding season in other British breeds of sheep demonstrates a strong correlation with latitude. On St Kilda, mortality rates in male sheep are higher than in females so that the ratio of rams to ewes at mating time is about 1:5. Competition amongst rams is intense. The optimal time for mating and the place of ram lambs in the social system are discussed.     

6. ANOTHER NOTE ON SAROTHRURA ELEGANS

Summary

Dowsett-Lemaire, F. 1983. Studies of a breeding population of Waller's Redwinged Starlings in montane forests of south-central Africa. Ostrich. 54:105-112.

The breeding biology and behaviour of Waller's Redwinged Starling Onychognuthus walleri was studied for two seasons in forest patches on the Nyika Plateau, 2 200 m ad. (Mala?i-Zambia). In general behaviour (e.g. strong pair bond, fidelity to the nest site), O. walleri resembles other species of the genus. Twenty-six egg-laying records are from late August to mid-November (i.e. end of dry season to early rains). Suitable nest sites (natural holes in trees) seem to be in short supply, and the non-breeding population is far in excess of the breeding one. Incubation periods lasted 13 days (2) to 16 days (1). One nestling period was 29 days. Insects are more important than fruits in the diet of nestlings. Annual breeding productivity is low (0,5-0,6 young/breeding pair) because of heavy nest predation, and at tunes insect-food shortages leading to starvation of young. There were few re-laying attempts, and only one abnormal attempt at a second brood.

Two other congeneric species, the Slenderbilled Redwinged Starling O. tenuirostris and the African Redwinged Starling O. morio also breed on the Nyika. Notes on their feeding habits, numbers and nest sites are given. One nest site of O. tenuirostris on a wet rock face by waterfalls was taken over by O. morio in the following season.     

Distribution, abundance and breeding cycle of the Australian sea lion Neophoca cinerea (Mammalia: Pinnipedia)

Surveys of the Australian sea lion Neophoca cinerea were conducted throughout its range in Western and South Australia between December 1987 and February 1992. Almost every island was visited between Houtman Abrolhos and The Pages ( n = 255), many of them more than once.
Sea lions breed on at least 50 islands, 27 in Western Australia and 23 in South Australia. Of the 50 breeding sites, 31 have not been reported previously. A further 19 islands may also support breeding colonies. A total of 1,941 pups was counted and pup production was estimated at 2,432. Only five colonies produced more than 100 pups each and they accounted for almost half of the pup production. Most of these colonies are near Kangaroo Island, South Australia. A breeding cycle of 17–18 months has been reported for N. cinerea at Kangaroo Island and on the west coast of Western Australia; this was also noted at another 11 islands where repeated visits coincided with breeding. No evidence was found for breeding seasons shorter or longer than 17–18 months. The breeding season was not synchronized between islands, as it is in other pinnipeds. A predictive model is developed to estimate the population size from pup production figures. It indicates that pup numbers should be multiplied by between 3.81 and 4.81 to estimate the total population size just before the pupping season begins. This leads to estimates of 9,300–11,700 for the total population, considerably greater than earlier estimates.
Causes of the unique reproductive cycle of N. cinerea are unknown, but we hypothesize that it results from living in a temperate climate in some of the most biologically depauperate waters of the world. It is also clear that day length and water temperature cannot act as exogenous cues for implantation of the blastocyst; the physiological events of gestation must, rather, be cued endogenously.     

禽流感发生后青海湖水鸟的种群现状

于2006年和2007年4~9月,在青海湖对水鸟的资源状况进行了调查。结果表明,青海湖地区迁徙水鸟的多样性呈季节性变化。春季迁徙期水鸟多样性较高,水鸟的种类和数量都较为丰富;进入繁殖期以后,各地点的水鸟多样性趋于下降;随着秋季迁徙期的来临,水鸟多样性又再度升高,水鸟的种类和数量接近或超过春季迁徙期。在春季迁徙期,布哈河口、铁卜恰河口、泉湾和尕日拉的斑头雁(Anser indicus)、棕头鸥(Larus brunnicephalus)、渔鸥(L.ichthyaetus)、普通鸬鹚(Phalacro coraxcarbo)和赤麻鸭(Tadorna ferruginea)5种水鸟的数量都较多,致使种间相遇几率也较高;进入繁殖期以后,尕日拉的种间相遇率降低,而蛋岛和黑马河的种间相遇率有所增加,其余如布哈河口、铁卜恰河口和泉湾仍维持较高的水平;秋季迁徙期5种水鸟大多以集群的方式进行活动,主要集中在少数几个地点,如布哈河口、泉湾和黑马河,因此这三处的种间相遇率随之增加。最后,有针对性地提出了禽流感监测和保护管理建议。     

OBSERVATIONS ON THE COMMUNAL ROOSTING OF AFRICAN BLACK OYSTERCATCHERS

Hockey P. A. R. 1985. Observations on the communal roosting of African Black Oystercatchers. Ostrich 56: 52–57.

There are currently three main hypotheses for the adaptive significance of avian communal roosts: physiological advantages, predator avoidance and information centres. The African Black Oystercatcher Haematopus moquini is territorial throughout the year and forms communal roosts during the nonbreeding season, but does not breed communally. Roosts generally are small, and site fidelity is high. Roosts are normally sited on a rocky promontory with adjacent offshore rocks (west coast), or in flat areas with extensive all-round visibility. The main predators of African Black Oystercatchers are nocturnal terrestrial mammals and nocturnal communal roosts are larger and more tightly packed than daytime roosts. Breeding birds do not roost communally during the breeding season and at this time of year mortality due to mammal predators at a study site in Saldanha Bay was greatest (X² = 9.46; p<0.01). It appears therefore that predator avoidance is an important adaptive feature of communal roosting in this species.     

Variation in the timing of the reproductive season among breeds of sheep in relation to differences in photoperiodic synchronization of an endogenous rhythm.

Photoperiod may regulate seasonal reproduction either by providing the primary driving force for the reproductive transitions or by synchronizing an endogenous reproductive rhythm. This study evaluated whether breed differences in timing of the reproductive seasons of Finnish Landrace (Finn) and Galway ewes are due to differences in photoperiodic drive of the reproductive transitions or to differences in photoperiodic synchronization of the endogenous rhythm of reproductive activity. The importance of decreasing photoperiod after the summer solstice in determining the onset and duration of the breeding season was tested by housing ewes from the summer solstice in either a simulated natural photoperiod or a fixed summer-solstice photoperiod (18 h light:6 h dark; summer-solstice hold). Onset of the breeding season within each breed did not differ between these photoperiodic treatments, but Galway ewes began and ended their breeding season earlier than Finn ewes. The duration of the breeding season was shorter in Galway ewes on summer-solstice hold than on simulated natural photoperiod; duration did not differ between photoperiodic treatments in Finn ewes. The requirement for increasing photoperiod after the winter solstice for initiation of anoestrus was tested by exposing ewes from the winter solstice to either a simulated natural photoperiod or a winter-solstice hold photoperiod (8.5 h light:15.5 h dark). Onset of anoestrus within each breed did not differ between these photoperiodic treatments, but the time of this transition differed between breeds. These observations suggest that genetic differences in timing of the breeding season in Galway and Finn ewes do not reflect differences in the extent to which photoperiod drives the reproductive transitions, because neither breed requires shortening days to enter the breeding season or lengthening days to end it at appropriate times. These findings are consistent with the hypothesis that photoperiod synchronizes an endogenous rhythm of reproductive activity in both breeds and that genetic differences in timing of the breeding season reflect differences in photoperiodic synchronization of this rhythm.     

Evidence for genetic differentiation among Caspian tern (Hydroprogne caspia) populations in North America

The Caspian tern (Hydroprogne caspia) is a globally distributed seabird that breeds throughout North America, generally in low numbers. Many colonies are threatened by habitat loss and pollution. Additionally, adult terns compete directly with salmonid stocking programs on the west coast, where a large proportion of the fish they feed their young are stocked salmon smolts. North America colonies have been classified into five ‘breeding groups’ based on banding data and geography. To help delineate effective management units, we characterized variation in mitochondrial DNA (488 base pair fragment of cytochrome b) and five microsatellite loci among 111 terns from six sites representing three of the North American breeding areas. We found significant range-wide population differentiation (cytochrome b: global Φ_ST = 0.12, P < 0.01; microsatellites: global F_ST = 0.094, P < 0.001). Pacific Coast sites differed genetically from sites east of the Rocky Mountains, and sites in Central Canada differed from those in the Great Lakes region. Gene flow among these three regions appears to be restricted. Thus, our results indicate that at least three of the breeding regions delineated using banding data and geography should be treated as separate management units.     

Biannual breeding and moult-breeding overlap of the Chestnut-bellied Starling Spreo pulcher

At Kano, Nigeria, the Chestnut-bellied Starling Spreo pulcher has two distinct breeding seasons, a long one from the late dry season to the early rains (February to June) and a short one in September, October and rarely November following the rains. Males have enlarged testes from February to October, so the breeding periods are probably determined by the reproductive condition of the females. Most individuals breed in both periods but some breed only in the pre-rains period. Adult wing-moult begins in March and April, overlapping with any breeding attempts in the latter half of the pre-rains session; some birds continue to moult into the post-rains session. Post-juvenal wing-moult is from August to January for birds reared in the previous pre-rains period and is simultaneous with adult moult for birds reared in the post-rains period. An increase in ambient temperature may be the most important proximate cue determining the pre-rains and also the post-rains breeding periods. A correlation between moult-breeding overlap and co-operative breeding for some tropical birds is suggested and discussed briefly.     

THE BREEDING SEASONS OF AFRICAN BIRDS—2. SEA BIRDS.

1. All the available data, largely unpublished, are assembled for sea-birds breeding in African waters, about 36° N.-36° S.
2. An ill-defined breeding season by any species at any station is exceptional.
3. North of the Equator practically all sea-birds breed in spring or summer.
4. South of the Equator there is much more variation. Round the Cape there is a good deal of mid-winter breeding, mainly in stations affected by the warm Agulhas current.
5. On the east coast most of the breeding takes place in the period June–August from the Gulf of Suez (27° N.) to the mouth of the Zambesi (19° S.) and beyond, i.e. in the hottest months north of the Equator and the coolest months south of it.