Breeding ecology of the African Spoonbill Platalea alba in the Free State,South Africa

Kopij, G. 1997. Breeding ecology of the African Spoonbill Platalea alba in the Free State, South Africa. Ostrich 68 (2–4): 77–79.

The breeding ecology of the African Spoonbill is surprisingly little known. In the Free State, the number of nesting African Spoonbills appears to have declined; 120 nests in 11 colonies were located in 1972–1973, compared to 32 nests in four colonies in 1993–1996 (though this later survey may have missed a few small colonies). In 1976–1977, a colony with 15 active spoonbill nests was monitored for an entire breeding season. Mean clutch size was 2.6 (n = 15); 56% of eggs hatched; 91% of hatched eggs resulted in fledglings; and chicks fledged from 53% of nests. The main food of spoonbill chicks was frogs, mainly Rana angolensis and Xenopus laevis, and aquatic invertebrates.     

Population Genetic Study of Mitochondrial DNA in Roseate Spoonbill (Aves; Platalea ajaja) Breeding Colonies from the Pantanal Wetlands, Brazil

Five breeding colonies of the Roseate spoonbill (Aves: Platalea ajaja) from two Brazilian wetland areas (Pantanal and Taim marshes) were sampled, and domain I of the mitochondrial DNA control region (483 bp) was sequenced in 50 birds. The average haplotype diversity (h = 0.75, s = 0.071) and average nucleotide diversity (pi = 0.004, s = 0.003) were evaluated, and nonsignificant differences were found among the colonies studied. The lack of differentiation among breeding colonies revealed by AMOVA analysis was explained either as a consequence of high gene flow or recent expansion. The significantly negative results of the neutrality tests (Fu's F ( s ) = -23.271, P < 0.01; Tajima's D = -1.941, P < 0.01) associated with the star shape of the haplotype tree and mismatch distribution data are evidence supporting the idea that these populations underwent a recent demographic expansion in the Pantanal region. The average time since the expansion is estimated to be 25,773 years, and this agrees with a period of increased moisture that occurred during the last glacial period.     

Sperm Competition and Copulation Intervals of the White Spoonbill (Platalea leucorodia,Aves, Threskiornithidae)

Some aspects of sperm competition were studied in the white spoonbill (Platalea leucorodia) breeding in Doñana National Park (SW Spain). Shorter pair copulation intervals occurred during the prelaying period, when females were subjected to a relatively high frequency of extra-pair copulations. Pair copulation intervals with an intermediate extra-pair copulation by the male mate were longer than those without extra-pair copulation. This result indicates that males need a time of recovery between copulations before they can perform another. Extra-pair copulations by the females did not affect the length of intervals between pair copulations. There were no differences between the lengths of the intervals between an extra-pair copulation by the female and the following pair copulation for cases in which the male mate detected an intruder male attempting copulation with his mate and those in which the intruder remained undetected. However, the correlations obtained between copulatory intervals for detected and undetected cases suggest a copulatory response by their mates, although affected by the required recovery time between copulations by the males. Finally, since extra-pair copulations mainly occurred while male mates were collecting nest material, they engaged in this activity shortly after pair copulations, probably to avoid a last-male advantage under the sperm competition pressure.     

Genetic structure in Brazilian breeding colonies of the Roseate Spoonbill (Platalea ajaja, Aves: Threskiornithidae)

Roseate Spoonbills (Platalea ajaja, Linnaeus) are wading birds present in two of the most important Brazilian wetlands: the Pantanal wetlands and Rio Grande do Sul marshes. Natural populations of these species have not been previously studied with variable nuclear molecular markers. In order to support decision making regarding the management and conservation of these populations, we estimated and characterized the distribution of genetic variability among five Brazilian breeding colonies. The average observed heterozygosity in Brazilian Roseate Spoonbill populations (Ho = 0.575) did not differ significantly from the value determined in a U.S. wild-caught sample of 15 individuals, using data generated by the same set of microsatellite loci. Considering that the U.S. population underwent a recent reduction in size, we discuss this result supposing that the U.S. population was not genetically affected or that both populations had suffered a bottleneck. Global F(ST) indicated the lack of genetic differentiation among colonies, indicating the occurrence of past and/or present gene flow among them. Analysis of molecular variance revealed that most of the genetic variation is distributed within the colonies. Results are explained by a recent origin of colonies or by high levels of gene flow. Management decisions should take into consideration the fact that, even in the presence of high genetic exchange, ecological adaptations to different environments are important for species survival.     

Genetic Differentiation Among Populations of the Roseate Spoonbill (Platalea ajaja; Aves: Pelecaniformes) in Three Brazilian Wetlands

Effective population size, levels of genetic diversity, gene flow, and genetic structuring were assessed in 205 colonial Roseate spoonbills from 11 breeding colonies from north, central west, and south Brazil. Colonies and regions exhibited similar moderate levels of diversity at five microsatellite loci (mean expected heterozygosity range 0.50–0.62; allelic richness range 3.17–3.21). The central west region had the highest Ne (59). F _ST values revealed low but significant genetic structuring among colonies within the north and within the south regions. Significant global genetic structuring was found between the northern and central western populations as well as between the northern and southern populations. An individual-based Bayesian clustering method inferred three population clusters. Assignment tests correctly allocated up to 64% of individuals to their source regions. Collectively, results revealed complex demographic dynamics, with ongoing gene flow on a local scale, but genetic differentiation on a broader scale. Populations in the three regions may all be conserved, but special concern should be given to central western ones, which can significantly contribute to the species’ gene pool in Brazil.     

艾比湖大白鹭的繁殖及雏鸟生长发育模式

2009年3—10月对新疆艾比湖大白鹭(Egretta alba alba)的巢、卵及雏鸟的生长发育模式进行了研究。结果表明,大白鹭的巢基厚度大于巢深(t=6.06,P0.01),巢外径远大于巢内径(t=21.53,P0.01),其目的是增加巢的稳定性和减少幼鸟跌出巢外的概率;窝卵数3～5枚(3.86±0.69),卵重44.00～60.00g(53.94±3.96),卵体积47.18～62.00cm3(55.19±4.09);双亲孵卵(26～28d),共同育雏(55～60d)。测量了4巢13雏26日龄以内的生长发育数据,并利用Gompertz方程对雏鸟的主要生长指标进行拟合,拟合结果将雏鸟生长发育划分为3个阶段:1)器官形成,生长速度准备加快的时期;2)物质积累,生长速度加快并逐渐过渡到中速时期;3)由物质积累逐渐过渡到物质消耗大于积累,生长速度较慢,雏鸟准备出飞。     

Breeding biology of the Barn Owl Tyto alba in central Mali

Data were obtained on 178 clutches of African Barn Owls in central Mali from four breeding seasons during 1979–1983. Significantly more clutches were laid in 1979–1980 and significantly fewer in 1980– 1981 than the average for the 4 years and there were significantly more clutches laid in the middle period of the annual breeding season. The egg volume was significantly smaller at the beginning of the breeding season and significantly larger in the middle than the overall mean with eggs of second clutches being larger than those of first clutches. The clutch size was 605 eggs of which 479 hatched. The number of young fledged per successful nest was 319 and was 1 83 for all nesting attempts. The month was the only variable shown to affect significantly the clutch size, eggs hatched and fledging rate, the highest success rates being associated with the middle of the breeding period. The average interval between the hatching of eggs was 2–31 days. Survival rates (47'1%) to fledging were significantly affected by year (1981–1982 being the least) and month (mid-season birds the best). The order of hatching significantly affected age at death or disappearance, the first-hatched birds surviving the longest. The year significantly affected age at fledging, the young from the year in which most clutches were laid leaving the nest at the youngest age and those associated with the year having the least number of clutches remaining in the nest the longest. The month of hatching also affected fledging age, birds at the extremes of the breeding season fledging at older ages. The discussion compares these data with those from elsewhere.     

黑脸琵鹭是怎样走向濒危的

黑脸琵鹭是一种全球性濒危珍稀鸟类．该物种已被收录于国际自然保护联盟(IUCN)“红皮书”,亚洲鸟类红皮书和中国濒危动物红皮书《鸟类》,等级为“濒危”,并建议列为国家Ⅰ级重点保护动物。     

Breeding system and fruit set in African Marantaceae

Marantaceae are a pantropically distributed family of perennial herbs and lianas in the understory of tropical rainforests. They are characterized by a unique pollen transfer mechanism. To understand its functional significance and evolution, field investigations have been conducted in Gabon.Data from 28 (of 35) species from Central Africa are achieved. The pollen–ovule ratio (34–140:1; exception Sarcophrynium 2.5:1) falls into the range of facultative autogamous species. All investigated species were proven to be self-compatible; however, only two were autogamous. Natural fruit set was generally low (10.9 ± 10%). The highest natural fruit set was found in Marantochloa purpurea (29.7%), Ma. grandiflora (33.5%) and the two autogamous species Halopegia azurea (31%) and Marantochloa leucantha (35%). Considerable higher fruit set could be reached in all species by hand-self-pollination.We conclude that autogamy is generally avoided through herkogamy based on secondary pollen presentation on the back of the style head – a central component of the specific pollen transfer mechanism. However, with respect to the consecutive visit of pollinators to several flowers of the same individual geitonogamy cannot be excluded. The aggregated pollen transfer via the explosive pollination mechanism might be interpreted as an adaptation to low pollinator visitation rate, pollen limitation might explain the low fruit set.     

Breeding seasons and laying patterns of the southern African Ostrich Struthio camelus

Wild Zimbabwe Ostriches Struthio camelus were studied during four successive years. Information on breeding seasons and laying patterns was compared with that of domesticated South African hybrid Ostriches in Bophuthatswana. In wild populations laying occurred mainly from July to December or early January, while domesticated birds continued until at least the end of February. Domesticated birds normally laid about 16 eggs in succession, one every second day. There was marked synchronisation of laying and the middle of each successive peak in egg production was about 6 weeks from the preceding peak. Wild birds laid up to eight eggs in any one nest, and normally clutches were contributed by three females, the average combined clutch being 12 or 13 per nest. Circumstantial evidence suggests that individual females may lay in more than one nest during a single laying sequence. Comparisons between rainfall patterns and laying rhythms proved inconclusive.     

Breeding phenology in relation to NDVI variability in free-ranging African elephant

The phenology of reproduction is often correlated with resource availability and is hypothesized to be shaped by selective forces in order to maximize lifetime reproductive success. African elephants have the distinctive life history traits of a 22 month gestation and extended offspring investment, necessitating a long-term strategy of energy acquisition and reproductive expenditure to ensure successful offspring recruitment.
We investigated the relationship between the reproductive phenology of a wild elephant population and resource availability using remotely sensed Normalized Differential Vegetation Index (NDVI) data as a measure of time-specific primary productivity and hence forage quality.
The initiation of female elephants' 3+yr reproductive bout was dependent on conditions during the season of conception but timed so parturition occurred during the most likely periods of high primary productivity 22 months later. Thus, the probability of conception is linked to the stochastic variation in seasonal quality and the phenology of parturition is related to the predictable seasonality of primary productivity, indicating elephants integrate information on known current and expected future conditions when reproducing.
Juvenile mortality was not correlated with ecological variability, hence female fecundity rather than calf mortality appears to drive demographic processes in the study population.
Extreme climatic events, such as those associated with the El Niño-Southern-Oscillation (ENSO), acted to synchronize female fecundity in the population. This study suggests that the relationship between fecundity and ecological variability instigates the characteristic demographic fluctuations in elephant populations, rather than the mortality-driven fluctuations observed in many ungulate populations.