Showing papers in "Ostrich in 2003"

The importance of roads and road verges for raptors and crows in the Succulent and Nama-Karoo, South Africa

Abstract: The behaviour and activities of 6 458 raptors (Accipitridae and Falconidae) and 1 947 Corvidae in the Karoo, South Africa, were recorded during the period January 1988 to June 2000 (n = 208 surveys) over a total distance of 90 012km. A significantly larger proportion of raptors and corvids were recorded foraging in road verges, or flying along roads than foraging or flying over rangelands. About 21% of all observations of crows feeding or foraging were associated with road-kills, whereas less than 2% of observations of feeding and foraging Accipitridae and Falconidae were associated with road-kills. The most frequent Accipitridae feeding on road-kills were Pale Chanting Goshawk (Melierax canorus), Yellow-billed Kite (Milvus migrans parasitus) and Jackal Buzzard (Buteo rufofuscus). There was no seasonal pattern in the number of crows feeding on roadkills, although there was a trend for more mammals to be killed on the roads, and thus more available food, in winter (June). It is likely that Accipitridae and...

Phylogenetic relationships of African sunbird-like warblers: Moho (Hypergerus atriceps), Green Hylia (Hylia prasina) and Tit-hylia (Pholidornis rushiae)

Abstract: Pholidornis, Hylia and Hypergerus are monotypic songbird genera that share insectivorous feeding habits and a common habitat in West African forests. Each of these genera has some sunbird-like characters as well as other characters that suggest affinities to sylvioid warblers. We briefly review previous phylogenetic hypotheses for these taxa and then present an analysis based on over 2 000 bases of mitochondrial sequence data for a broad range of Old World songbirds representing most families in Sibley and Ahlquist's (1990) superfamilies Passeroidea and Sylvioidea. Our analyses confirm the placement of Hypergerus and its sister taxon Eminia within a larger monophyletic family of African warblers Cisticolidae. We also find strong support for a sister relationship between Pholidornis and Hylia and evidence that this clade represents just one lineage in a diverse assemblage of Old World warblers that is probably paraphyletic or polyphyletic with respect to other sylvioid families. While a definitive placemen...

A review of foraging and feeding behaviour, and associated anatomical adaptations, in Afrotropical nightjars

Abstract: Nightjars (Caprimulgidae) in the Afrotropical Region feed almost exclusively on night flying insects, which they hunt during twilight and moonlight. Without the benefit of echolocation, they detect prey visually before pursuing and capturing it in this dim light. They are superbly equipped to do so, utilising a suite of anatomical adaptations in different hunting strategies. This paper, based on a comprehensive literature review, examines the facts and fallacies surrounding those adaptations and strategies. The adaptations, common to most of the species, are reflected mainly in the greatly enlarged eyes and mouth; the greatly reduced bill, tongue and crop; the structure of the lower jaw and the rictal bristles; and the sensitive nature of the palate. Hunting strategies vary between species, and even within species, according to habitat, prevailing light conditions and availability of insect prey. The most commonly used strategy, employed by all species at times, is to hawk single insects from a terrestria...

A field survey to investigate why nightjars frequent roads at night

Abstract: Nightjars throughout the Afrotropical Region regularly frequent roads at night and during the twilight of dusk and dawn. Most species exhibit this behaviour and numerous individuals are killed by road traffic. Many theories have been advanced to explain the presence of nightjars on roads at night, but very little fieldwork has been carried out to test them. For a period of a year we carried out a weekly survey of nightjars on a selected road network near Harare in Zimbabwe. All nightjar encounters were documented in relation to variations in road surface, road width, adjacent habitat, arc of sky visible and other variables, such as the time of night, moon phase and weather conditions. None of these factors provided a complete explanation for the presence of nightjars on the roads surveyed. Neither were any of the nightjars seen dust bathing, taking grit or picking up insects from the road. Many were seen actively hunting flying insects, especially at dusk, and palpation of the stomachs of those caught con...

Patterns of endemism in African birds: how much does taxonomy matter?

Abstract: It has been suggested that the ‘right' biogeographic patterns will only arise with a species concept reflecting the finest splitting of terminal phylogenetic branches. The significance of taxonomic resolution was assessed using distributional data for all resident African land-birds, held at the Zoological Museum of Copenhagen. The primary database (in a one-degree geographical grid) served as a template for creating two new databases: one, where the distributional records were allocated to species according to the ‘Speciation Atlases' for African birds (Hall and Moreau 1970, Snow 1978) and two, according to the finest taxonomic splitting that has since then been suggested in the literature. With this spatial resolution, the species richness pattern is almost exactly the same whether old or new taxonomy is used. The endemism follows another pattern with marked local aggregates. The location of principal aggregates are quite robust to recent splitting, although a slightly more complex structure appears. Also some small new areas of endemism emerge, each with 2–3 narrow endemics. However, large portions of African savannah and lowland rainforest are still characterised by a total lack of narrow endemism. Based on the current understanding of diversification processes and adaptive re-distribution it is suggested that the uneven distribution of narrowly endemic and widespread species will persist even if it were possible, in the future, to define terminal taxa in a consistent way. (Ostrich: 2003 74(1&2): 30–38)

Molecular systematics of Alethe, Sheppardia and some other African robins (Muscicapoidea)

Abstract: Phylogenetic relationships between species of akalats (Sheppardia) and alethes (Alethe) were derived from mitochondrial and nuclear sequence data, and phylogeographic pattern was also investigated in three widespread species (two Alethe and one Sheppardia) endemic to the African lowland rainforest biome. Co-distributed species of Alethe and Sheppardia showed similar spatial relationships between the Guineo-Congolian biome and the Western Rift mountains, and preliminary area relationships are shown for species of Sheppardia and Alethe distributed in the Cameroon highlands, the woodland areas north and south of the lowland forest block, and east African montane and lowland forest. Within widespread species, phylogeographic pattern was generally similar, with long branches between Upper and Lower Guinea populations, and between eastern and western Congolian populations. At the interspecific level, the nuclear intron used gave more resolution than the mitochondrial data, which gave poor resolution at basal no...

Waterbird populations at the Orange River mouth from 1980-2001: a re- assessment of its Ramsar status

Abstract: The Orange River mouth (ORM), at the end of the longest river in South Africa, is one of few perennial wetlands on the arid south-west African coast. The ORM supports a large number of waterbirds, with a maximum of 20 653-26 653 individuals of 57 species being recorded in December 1985. Because of its importance for waterbirds, the ORM is recognised as a Ramsar site and an Important Bird Area. Since being designated a Ramsar site in 1991, however, the number of waterbirds has decreased (by c. 74% since the first two surveys in 1980 and 1985). During 13 surveys conducted from December 1995 to August 2001 an average of 6 873 (±1 719 SD; n = 6) and 5 547 (±2 039 SD; n = 7) individuals were recorded during summer and winter, respectively. This decrease, in conjunction with the degradation of the c. 300ha saltmarsh resulted in the ORM being placed on the Ramsar Convention's Montreux Record in 1995. The decrease in the number of waterbirds at the ORM is mainly attributable to the absence of large numbers of Cap...

The Karoo Thrush (Turdus smithi Bonaparte 1850), a southern African endemic

Abstract: The Olive Thrush ( Turdus olivaceus ) species complex is characterised by striking geographical phenotypic variation. Recent consensus has been to recognise three assemblages (1) the olivaceus group restricted to southern Africa, (2) the swynnertoni group of the Zimbabwean and southern Malawi highlands and (3) the abyssinicus group of the montane highlands of eastern and central Africa. We re-examined the status of taxa in the olivaceus group of southern Africa, with specific reference to the central-western taxon T. o. smithi using both morphological and molecular evidence. Sequence divergence between T. o. smithi and other members of the olivaceus group averages 3.5% for the cytochrome-b gene and 4–4.5% for the NADH subunit 3 gene of the mitochondrial DNA. There is also both morphological (biometric and plumage) and molecular support for the recognition of T. smithi as a separate species, the common name of which we suggest should be Karoo Thrush. (Ostrich: 2003 74(1&2): 1–7)

Territoriality of Cape Sugarbirds (Promerops cafer) between and within breeding seasons

Abstract: Cape Sugarbirds are southern African endemics, found in fynbos vegetation of the Western and Eastern Cape Provinces of South Africa, and they feed almost exclusively on the nectar of Protea inflorescences. Breeding male Sugarbirds are highly territorial and defend resources for themselves, their mates and their offspring. Sugarbirds, however, often leave their breeding territories in search of food during the dry season and return to the same breeding sites each year, thus experiencing an annual cycle of movement from one food source to another. Male territory size as well as breeding success, were determined over two breeding seasons for a population in the Helderberg Nature Reserve in the Western Cape Province. Sugarbird fledgling success was significantly greater for males defending large territories. Males moved or increased the size of their territories between seasons, possibly to improve breeding success, but no changes in territory size were observed during the breeding season.

Biomechanical features of the bill and and jaw apparatus of cuckoos, turacos and the hoatzin in relation to food acquisition and processing

Abstract: A morphofunctional analysis of the feeding apparatus was conducted from an evolutionary perspective on the hoatzin (Opisthocomidae), some cuckoos (Cuculidae) and some turacos (Musophagidae). These ...

The influence of vegetation structure on bird communities in a Karoo village, South Africa

Abstract: We surveyed the bird species richness and abundance at 12 sites in gardens and four sites in natural woodlands at Prince Albert, Western Cape, South Africa, over a two-month period, from 14 September to 15 November 1999. Bird numbers were estimated using point counts. Of a total of 75 bird species recorded, 34 species occurred in both garden and natural sites, 23 species only in gardens and 18 species only in natural woodland. The sites in natural habitats had the greatest similarity between species. The commonest species nesting in gardens during this study was the Cape Sparrow ( Passer melanurus ), followed by the Laughing Dove ( Streptopelia senegalensis ), and Greater Striped Swallow ( Hirundo cucullata ). Bar-throated Apalis ( Apalis thoracica), Namaqua Warbler ( Phragmacia substriata ), Fiscal Flycatcher ( Sigelus silens ) and Common Fiscal ( Lanius collaris ) nests were only observed at the natural sites. Southern Double-collared Sunbird ( Cinnyris chalybea ) and Cape White-eye ( Zosterops capensis ) nested in both natural and garden sites. Tree hole-nesting species were rare in both gardens and natural woodland, but this reflects the paucity of suitable sites rather than the rarity of the species per se. With the exception of two sites that lacked nectarivores, all foraging guilds were represented at all sites. There was a marked difference in numbers of insectivorous, granivorous and omnivorous species between the natural woodland sites and the garden sites. The gardens showed a gradient in species richness from the gardens with structurally simple vegetation (bare ground) through to the richest species assemblages in the structurally most diverse habitats (trees). However, this gradient was less clear than expected. Structurally fairly simple vegetation (but abundant ‘flowers') had species numbers almost as high as the woodland sites, and higher than the garden tree sites. (Ostrich: 2003 74(3&4): 209–216)

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

Abstract: 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. (Ostrich: 2003 74(1&2): 110–116)

Moult, breeding season, mass, wing length, and dispersal in Cape Robins ( Cossypha caffra ) and Olive Thrushes ( Turdus olivaceus ): results from mist-netting garden birds

Abstract: We compared a data set from the Western Cape, South Africa (GDU, n = 170 Olive Thrushes ( Turdus olivaceus ), n = 475 Cape Robins ( Cossypha caffra )) with our captures in the Eastern Cape, South Africa (n = 197 Olive Thrushes, n = 203 Cape Robins). In both regions Olive Thrushes began moult in December-January, while wing-moult lasted for 89 days in the Western Cape compared to 53 days in the Eastern Cape. Cape Robins began moult in early November in the Western Cape, early January in the Eastern Cape and again the duration of wing-moult was longer in the Western Cape (64 days) than in the Eastern Cape (50 days). For both species the start of moult coincided with the end of the breeding season. Cape Robins were heavier and longer-winged in the Western Cape than in the Eastern Cape. There was no significant difference in mean mass or mean wing length of the Olive Thrush between the two provinces. Both ringing and atlas data suggest that Cape Robins are relatively more common than Olive Thrushes in the Western Cape, but not in the Eastern Cape. In the Eastern Cape we observed colour-ringed robins (n = 2) and thrushes (n = 2) on their breeding territory in all months of the year, suggesting that some individuals of both species are strongly resident. (Ostrich: 2003 74(1&2): 81–86)

Short Note Long-billed Tailorbirds ( Orthotomus moreaui ) rediscovered at Serra Jeci, northern Mozambique

Abstract: The Long-billed Tailorbird, Orthotomus (Artisornis/Apalis) moreaui, is listed as Critically Endangered on the basis of its very small and fragmented population (criterion C2a; BirdLife International 2000). It is known from only two localities some 950km apart: the East Usambara Mountains of north-east Tanzania and the Serra Jeci (Njesi Plateau) of Niassa Province, northern Mozambique. The nominate race is scarce at the East Usambaras (Cordeiro et al. 2001), but nothing is known about the current status of subspecies sousae from Mozambique (BirdLife International 2000). The only information on Long-billed Tailorbirds in Mozambique dates from 1945, when Jali Makawa spent 16 days in the Unango district, collecting birds on the Njesi Plateau (labelled Serra Jeci on modern maps) at the behest of Con Benson (Benson 1945, 1946). Among the 29 bird species collected by Makawa were seven specimens of Long-billed Tailorbird, which Benson described as a new subspecies (Benson 1945). One of the conservation targets identified by BirdLife International (2000) was an assessment of the status of Long-billed Tailorbirds at Serra Jeci, reiterating the call made by Collar and Stuart (1985). We made a brief visit to Serra Jeci during July 2001 and are pleased to report that the area remains virtually undisturbed by humans, and that Longbilled Tailorbirds still occur at this site.

Short Note Another reason for nightjars being attracted to roads at night

Abstract: (2003). Another reason for nightjars being attracted to roads at night. Ostrich: Vol. 74, No. 3-4, pp. 228-230.

Immediate effects of a fire on birds and vegetation at Ankarafantsika Strict Nature Reserve, NW Madagascar

Abstract: The use of fire for cultivation and to promote the growth of grasses for grazing has long been indicated as the principal cause of the transformation of Malagasy forests into secondary grasslands (Humbert 1927). In 1985 an estimated 85% of the moist (eastern) forest had already disappeared (Sayer et al. 1992). Deforestation is still more dramatic in western Madagascar. Since settlement of this region by humans, an estimated 97% of the island’s dry deciduous western forests have been destroyed, and those remaining are extremely fragmented (World Wildlife Fund 2001). Despite the importance of western dry forests for some threatened endemics such as the White-breasted Mesite, Mesitornis variegata, or the Van Dam’s Vanga, Xenopirostris damii (BirdLife International 2000), there are no published studies, to our knowledge, dealing with the effects of fire on Malagasy bird communities. It could be predicted that forest birds would be negatively affected, particularly in the short term, by wildfires sparked by burning adjacent secondary grasslands. In contrast, opportunistic species could, as is commonly observed in continental Africa, benefit from prey escaping the fire (Dean 1987) or from better food availability shortly afterwards (Prodon and Pons 1993). In this context, even sparse observations on immediate reactions of birds to fire in Madagascar are of interest. Ankarafantsika Strict Nature Reserve, Mahajanga province, NW Madagascar, is one of the five largest fragments still remaining of western primary forest (World Wildlife Fund 2001). Despite its legal status, the reserve suffers from different forms of exploitation (pers. obs.). During the course of a field study on the effects of deforestation on bird communities we worked for nine days in the plateau of Besaboabe (16°10’S, 47°00’E). This is a sandy plateau covered by western dry deciduous forest and fire-maintained savanna, included in the Strict Reserve. During our stay in the area we involuntarily assisted a savanna burning (illegally set in the reserve) which we were then able to study.

A new mainland breeding locality for African Penguins, Bank and Crowned Cormorants on the Namib desert coast

Abstract: (2003). A new mainland breeding locality for African Penguins, Bank and Crowned Cormorants on the Namib desert coast. Ostrich: Vol. 74, No. 3-4, pp. 222-225.

Biogeographical zonation of African hornbills and their biotic and geographic characterisations

Abstract: We studied the geographic ranges of the 23 African hornbill species using countries as distribution units, to search for either groups of similar distributions (chorotypes) or gradual replacement of species as two different types of distribution patterns. We used a probabilistic classification method to distinguish between these two types of biogeographic patterns. Then we analysed the influence of climate, area, surface covered by different types of habitat, and human disturbance in each country, as well as biotic features of the species involving the habitat preference, feeding requirements and habits, body size, sexual dimorphism, and metabolic parameters, on the biogeographic patterns detected. We found that 20 species were significantly classified into three chorotypes. The western-central chorotype comprises nine species characterised by their preference for forest habitat and their low sexual body mass dimorphism. These species occur in 25 countries, characterised by their low range of temperatures...

Observations on the breeding biology of the Seychelles Fody on Cousine Island

Abstract: The Seychelles Fody, Foudia sechellarum, is a ploceid weaver occurring naturally on three islands in the Seychelles group in the Indian Ocean. The population on Cousine Island was studied between 30 June and 25 August 1997. The size of the population on the island was estimated at 458–614 individuals and densities varied in different habitat types. As Seychelles Fodies in non-breeding plumage are difficult to sex, we provide sexing criteria based on wing length. Breeding pairs form small, probably temporary, territories that are defended by both partners against other fodies, including the introduced Madagascar Fody, Foudia madagascariensis. The Seychelles Fody often breeds semi-colonially and we observed up to five nests close together. The birds are socially monogamous and both sexes share in nest building, nest defense and provisioning of the young. Only females incubate. Many nests were deserted before eggs were laid, including some that had been accepted by the female. Additional males and females we...

Status, biometrics, moult and possible relationships of the South African population of Roseate Tern

Abstract: The breeding population of Roseate Terns in southern Africa was estimated to be 250–260 pairs in 2000. Adult birds caught during nocturnal tern roost mist-netting on Bird Island and at Cape Recife, both in Algoa Bay, were closest to their North Atlantic counterparts in wing, bill, total head length, tail and mass measurements. Adult moult differs from that of other populations. The two series wing moult of adults begins in the austral winter and lasts through summer; three feather series may be present in the primary remiges of immature birds. Evidence at present points to reproductive isolation of the South African population and to a degree of migratory behaviour, the extent of which remains unknown. However, size, breeding periodicity and low inter-annual return rate of ringed adults in successive seasons suggests a possible link with the southern Madagascan population. (Ostrich: 2003 74(1&2): 74–80)

Long-billed Tailorbirds (Orthotomus moreaui) rediscovered at Serra Jeci, northern Mozambique

Abstract: (2003). Long-billed Tailorbirds (Orthotomus moreaui) rediscovered at Serra Jeci, northern Mozambique. Ostrich: Vol. 74, No. 1-2, pp. 141-145.

Population densities and community structure of birds in riverine forest in the lowveld of Swaziland

Abstract: Population density and community structure of birds were studied at three sites in riverine forest in the lowveld of Swaziland. Birds were surveyed monthly using a standard point count technique. A total of 101 species of birds was recorded. Species richness at the three sites ranged between 70–76 species. Population density was similar at the three sites and ranged between 24.0–31.2 birds ha -1 . Biomass of birds was also similar at the three sites. Resident birds accounted for 74% of all species, but made up 97% of the individuals and biomass. There was a relatively large number of vagrant species, but they only accounted for Acacia savanna and broadleaved woodland in Swaziland. (Ostrich: 2003 74(3&4): 173–180)

Diet of the critically endangered Seychelles Scops Owl, Otus insularis

Abstract: The only data previously recorded on the diet of the critically endangered, endemic Seychelles Scops Owl, Otus insularis, is from the stomach contents of a few museum specimens and analysis of one pellet. Data are presented on more than 400 prey items identified from pellets and video recordings of provisioning at two nests. Pellets comprised exclusively of invertebrate remains: Orthoptera (64%), Coleoptera (14%), arachnids (11%) and other invertebrates (11%). Similarly, 111 (76%) of all items identified during 145 provisioning visits at two nests were invertebrates. Seventy-three (66%) were identified to morphospecies and comprised Orthoptera (93%), arachnids (4%) and Lepidoptera (3%). The diet of scops owls inhabiting areas of different altitudes (180-700m asl) was similar. Identification of prey taxa and species suggests that a significant amount of foraging takes place from foliage and on tree trunks, not just on the ground.

Short Note Breeding activity and provisioning rates of Stripe-breasted Tits ( Parus fasciiventer ) at Bwindi Impenetrable Forest, Uganda

Abstract: At temperate latitudes, high mortality caused by severe winter weather or long-range migration leads to a disparity between adult population size and food availability in the spring, creating conditions in which most passerines are able to rear relatively large broods (Ashmole 1963). In contrast, the carrying capacity of tropical habitats, especially rainforests, is thought to show less pronounced seasonal variation, limiting food availability for breeding adults and breeding opportunities for their offspring (Skutch 1950, Lack 1968). Provisioning rates in tropical species are further constrained by relatively short day lengths (Lack 1947) and periods of heavy rainfall. Higher rates of nest predation may also influence clutch sizes in the tropics (e.g. Skutch 1949, but see Martin 1996), favouring the production of small, repeat clutches (Ricklefs 1969) during more extended breeding seasons. Thus, Blue Tits, Parus caeruleus, in Europe typically lay 10–12 eggs, forage for most of a 16 hour day and fledge 8–9 young over a 55–70 day breeding cycle (Perrins 1979, Dhondt 1992). In contrast, pairs of Southern Black Tits, P. niger, in the Transvaal lay only about 4–5 eggs, are limited to a 13 hour day, have a breeding cycle of c. 90 days, and normally rear only 1–2 young each year, often assisted by helpers (Tarboton 1981). African tit species have received little attention in comparison with their temperate congeners, and only three (subtropical) species, Southern Black Tit, Carp’s Tit, P. carpi, and Ashy Tit, P. cinerascens, have been studied in any detail (Tarboton 1981, Wiggins 2001). Such studies enable direct comparisons to be drawn between congeners, avoiding the potentially confounding effects of phylogeny. This paper describes breeding parameters of the Stripe-breasted Tit, P. fasciiventer, a restricted-range species found in equatorial montane forests of the Albertine Rift (Stattersfield et al. 1998). Observations on the timing of breeding and on provisioning rates of Stripe-breasted Tits are described, and compared with that of other tit species.

Cave breeding by African Penguins near the northern extreme of their range: Sylvia Hill, Namibia

Abstract: Only three mainland sites are known among the total 27 breeding colonies of the African Penguin, Spheniscus demersus: two in South Africa and one in Namibia. The latter is a unique cave site near the northern extreme of the species' range on the edge of the Namib Desert. To determine the colony size, long-term viability and any difference in breeding ecology relative to more southern sites we combined data from previous visits to the site with four visits in 2001. We found that about 240 to 300 birds use the Sylvia Hill cave, and about 90 nests are active with a laying peak in January. Eggs are laid on top of guano mounds not in burrows as is usual for this species. Smaller clutches (1.68 eggs/nest) but larger broods (x = 1.31 chicks/nest) were apparent in this colony than those farther south. Larger mean clutches farther south suggest a latitudinal trend in clutch size for Namibia's penguins. We found no evidence for a population decline over 17 years, and thus no evidence that birds at the periphery of ...

Size, plumage, moult and supposed hybrids of African Goshawks (Accipiter tachiro/toussenelii group) in DR Congo

Abstract: Parapatric A. tachiro sparsimfasciatus and A. toussenelii canescens are in a size cline from large east African to small west African birds. While their plumage colour is different, the pattern of spotting (juvenile) and barring (adult) of the breast feathers is similar. No general hybridisation is found in the contact region in Kivu: the plumage of some aberrant individuals can be due to great age or to individual variation. One supposed hybrid was obtained far from the contact region. I consider them as paraspecies. Based on direct evidence and on annual moult I conclude that the breeding period is prolonged in both taxa in equatorial DR Congo, and that it is seasonal in tachiro sparsimfasciatus in southern DR Congo. In the latter population, the postjuvenile moult starts probably just before the age of one year but it lasts many months, leaving the juvenile upper tail coverts in place for one more year. Plumage characteristics are related to habitat. The female of the woodland sparsimfasciatus is cryptically coloured, with individual variation, possibly helpful for ‘image avoidance'. The male is even more variable in colour, in part age related: a ‘sepia' morph is described for the first adult plumage. Older birds are grey with reddish flanks, becoming darker with age. The adult evergreen forest canescens shows enforcement of colourful advertising plumage and loss of sexual plumage dimorphism. The first adult is advertised by the late moult of the barred juvenile flank feathers in both sexes. Its juvenile is peculiar; it lacks breast spots, suggesting image avoidance, but possibly also character displacement or mimicry. (Ostrich: 2003 74(1&2): 18–29)

Effect of breeding timing on White-breasted Cormorant (Phalacrocorax carbo) reproductive success at a seasonally constant Kenyan lake

Abstract: White-breasted Cormorant ( Phalacrocorax carbo ) breeding timing and reproductive success were documented in 1995 and 1996 at Lake Naivasha, Kenya (0°49'S), considered to be seasonally constant. In both years, pairs breeding earlier fledged significantly more chicks per breeding attempt than pairs breeding later. Smaller brood sizes later in the season were responsible for 81% of the difference; nestling loss represented 19%. Sixty-three percent of the total nestlings lost were from the nests of pairs breeding late in the season. Starvation appeared to be the primary cause of nestling loss, but there was no evidence of a consistent seasonal decline in prey availability. Neither predation nor sibling aggression appeared to be a major factor, although the reproductive success of late-breeders was almost certainly reduced by conspecific interference from fledglings of early-breeding pairs. The likeliest explanation for the seasonal decline is that older, more experienced (and therefore more successful) birds tend to breed early in the season. (Ostrich: 2003 74(1&2): 102–109)

Armoured Bush Cricket attacks on nestling Red-billed Quelea (Quelea quelea)

Abstract: (2003). Armoured Bush Cricket attacks on nestling Red-billed Quelea (Quelea quelea) Ostrich: Vol. 74, No. 1-2, pp. 135-135.

An isolated population of Singing Cisticola, Cisticola cantans, in Angola

Abstract: (2003). An isolated population of Singing Cisticola, Cisticola cantans, in Angola. Ostrich: Vol. 74, No. 3-4, pp. 231-232.

Short Note Flightless Aldabra Rail ( Dryolimnas cuvieri aldabranus ) kills Black Rat ( Rattus rattus )

Abstract: Aldabra Rails, Dryolimnas cuvieri aldabranus, like many other rails and other island birds, are curious and inquisitive towards novel stimuli. This trait made their capture during the 1999 reintroduction to Picard Island on Aldabra Atoll (9°24’S, 46°20’E) (Wanless et al. 2002) relatively simple, but it probably also contributed to their extinction on all islands in the region where domestic cats, Felis catus, have become established (Benson and Penny 1971). Unlike many island birds that have lost nest-defence behaviour (Moors and Atkinson 1984), Aldabra Rails will vigorously defend nests against all threats (Abbott 1893). Black Rats, Rattus rattus, were introduced to Aldabra Atoll at some unrecorded date before 1890 (Stoddard 1971). Rats are aggressive nest predators on Aldabra (e.g. Frith 1976) and have been implicated in the extinction of several island species elsewhere (Atkinson 1985, Moors et al. 1992). During the 1999 Aldabra Rail reintroduction to Picard Island (Wanless et al. 2002), pairs of rails were temporarily housed in enclosures before being released. Remains of rail food in the enclosures regularly attracted Robber Crabs, Birgus latro, and Terrestrial Hermit Crabs, Coenobita spp., and probably rats too. On the morning of 8 November 1999, I entered an enclosure to feed the birds and noticed a dead rat inside. There was a bald patch of skin on the right-hand side of its head and the eyes had been eaten. A superficial examination revealed a depression in the region of the supra-occipital crest, beneath the bald patch, suggesting a blow to the head had fractured the skull. The rat, a medium-sized adult, had no other injuries and appeared to have been healthy and in good condition. I placed the dead rat outside the enclosure, intending to dissect it later. However, a Pied Crow, Corvus albus, flew off with the rat and ate it; I was unable to confirm the cause of death or obtain details of any other injuries to the rat. Nevertheless it seems that the rat was killed by a blow or blows to the head delivered by one or both rails in the enclosure. It is possible that aggressive behaviour in Aldabra Rails has been retained and strengthened by the presence of several native nestand nestling-predators on Aldabra: the aptly named Robber Crab, the Madagascar Coucal, Centropus toulou insularis, and the Madagascar Kestrel, Falco newtoni (pers. obs.). There are several accounts of rails interacting with rats (e.g. Penny and Diamond 1971, Frith 1977), all of which ended with rails successfully defending nests or food against rats. Rats are probably not significant predators of adult rails. Downy chicks, which are constantly guarded by adults, are also likely to be less vulnerable to rat predation than previously believed (contra Penny and Diamond 1971). Despite high densities of rats (Racey and Nicoll 1984), nestdefence behaviour by the rails, and the apparent ability to kill a reputedly aggressive predator, has quite possibly contributed to the rails’ survival and comparatively high nesting success on Aldabra (Penny and Diamond 1971, Wanless et al. 2002).