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.     

4. A FIELD NATURALIST'S PEREGRINATIONS. BIRD NOTES FROM A NORTHERN SECTOR OF SOUTHERN RHODESIA—Part III

Boyer, H. J. 1988. Breeding biology of the Dune Lark. Ostrich 59:30-37.

The peak of the breeding season of the Dune Lark Mirafra erythrochlamys occurred in January and February and was not dependent on rainfall. Most nests were domed, although one undomed nest was recorded. Ninety-one percent of clutches were of two eggs (mean = 1,9; range 1–2; n = 11). The eggs are described and measurements given. Incubation, by the female only, began with the laying of the second egg, and hatching occurred after 13–14 days. Growth and development of nestlings are described. The young left the nest after 12–14 days, and post-nestling parental care lasted for approximately one month. Sixty-one percent of eggs hatched. and 28% produced young which successfully left the nest. Most losses of eggs and young were the result of predation.     

INVESTIGATION ON THE CAPE GANNET

Most Cape Parrot, Poicephalus robustus, nests have been recorded in snags (standing dead trees) making monitoring of nest contents and nest activities difficult and dangerous. Here the breeding activity of a Cape Parrot pair in the cavity of a live Henkell's Yellowwood (Podocarpus henkellii) is presented. Four eggs were laid in early-August and three chicks successfully raised. Incubation period was estimated at 30–32 days. Two nestlings fledged successfully and one (the youngest) was removed because it was injured in the nest and would not have survived. Fledging period was estimated at 80 days.     

1. ADDITIONAL NOTES ON THE BIRDS OF BLOEMHOF DISTRICT

Olver, M.D. 1984. Breeding biology of the Reed Cormorant. Ostrich 55:133-140.

The breeding biology of the Reed Cormorant Phalacrocorax africanus was studied at Cedara Dam, Natal, South Africa, from 1973 to 1975. Breeding occurred from November to February and was preceded by a period of courtship. Mean clutch size was 3,6 eggs and mean egg measurements were 44,2 x 29,5 mm. The average incubation period was 23,3 days. Young leave the nest at 28 days when alarmed but cannot fly until 35 days old. Hatching success was 84,1%, and fledging success 60,6%.     

SYSTEMATIC NOTES ON BIRDS OF THE CAPE PROVINCE

Hofshi, H., Gersani, M. &; Katzir, G. 1987. Urban nesting of Tristram's Grackles Onychognathus tristramii in Israel. Ostrich 58: 156–159.

Urban nesting of Tristram's Grackles Onychognathus tristramii is described. Nesting in the town of Arad, Israel, was first observed in the summer of 1983. Breeding behaviour was recorded during two seasons, in six nests. The behaviour of Tristram's Grackles resembled that of related Onychognathus species. The birds were monogamous. Breeding was from March to the end of June, and nests were built in holes and crevices in unoccupied buildings, 6–20 m above the ground. The nest was deep, cup shaped and built predominantly of green Tamarix branches. Three to four eggs were laid. Only the female incubated, while the male guarded. Both parents fed the young on insects fruit and human food remains. The nestlings remained in the nest for approximately 30 days. Parents continued to feed the fledglings for a week after they had left the nest. The fledglings formed juvenile flocks, two weeks after they had left the nest. The adults might then raise a second brood. The process of urbanization of the grackles is discussed.     

ON THE LIFE-EXPECTANCY OF THE MATOPOS BLACK EAGLES

Oatley, T. B. 1982. The Starred Robin in Natal, Part 3: Breeding, populations and plumages. Ostrich 53: 206–221 The female Starred Robin Pogonocichla stellata constructs a domed nest of moss and dead leaves usually on sloping ground and well concealed in the herb layer. The normal clutch is three eggs laid on consecutive days. Incubation usually starts with the laying of the third egg. The mean size of 138 eggs was 22 x 16 mm. The female incubates the eggs for 16 to 18 days and intermittently broods the young for the fist five of the average 14-day nestling period. Both sexes feed the young from the time of hatching and parental care lasts for some 42 days after leaving the nest. Eggs are laid from October to December with 63% of clutches started in November. Data on sex ratios indicate a surplus of adult males in the population and annual survival rates are estimated at 0,84 for males and 0,76 for females. 51% of eggs laid in 60 nests give rise to fledged young. About 21.3% of eggs laid produce adults. The level of brood parasitism by cuckoos is relatively low. Most adult mortality occurs outside of the breeding seasons. Chilling and overnight starvation from January to March when incidence of late afternoon thunderstorms is highMaycause significant mortality. The subadult plumage appears to confer crypsis and enable the immature bird to reside in adult territories without harassment. AdultsMaybenefit through an effective reduction in competitive stress.     

4. UNUSUAL EXPERIENCES WITH BIRDS

Earlé, R. A. 1989. Breeding biology of the Redbreasted Swallow Hirundo semirufa. Ostrich 60: 13–21.

The two races of the Redbreasted Swallow Hirundo semirufa seem to have separate breeding seasons with the northern race H. s. gordoni breeding April-July, while most records for the nominate race fall in October-February. All nests studied were in concrete culverts less than 1 m high. Eggs laid in second clutches by individual females weighed significantly less than eggs laid in first clutches. Eggs hatched on average 16,2 days after incubation started or 18–21 days after the eggs were laid. Only females incubated. Chicks fledged 23–25 days after hatching and reached a maximum body mass of about 31,5 g on day 18 before a steady decline in mass until fledging. Most nesting failures resulted from infertile eggs or starvation of young in the nest (16,2% of all young starved). Overall breeding success was 60,6%. In all, 81,8% of first clutches produced fledglings but only 44,4% of second clutches. Over a three year period 4,9 young were produced per pair breeding in the area (1,6 young/pair/breeding season).     

Aspects of the breeding biology of the Chinspot Batis Batis molitor in Acacia savanna in Swaziland

Some aspects of the breeding ecology of the Chinspot Batis (Batis molitor) were studied in Mlawula Nature Reserve, north-eastern Swaziland. Nests were predominantly built in thorny bushes or trees. Eggs were laid between 20 September and 2 January. However there was a definite peak in November, during which the majority of eggs were laid. Nesting success in the Chinspot Batis was over 30%, while fecundity was 0.65 fledglings/pair/annum. Except for a single occasion, pairs did not double brood unless breeding failed or fledged chicks disappeared. Replacement nests, however, were the norm where a previous nest had failed. Adult batises were observed to feed predominantly on caterpillars and moths. Observations at the nest confirmed that batises fed predominantly moths and caterpillars to their nestlings. The rate at which nestlings were fed depended on their age, older chicks being fed more frequently than younger ones. The correlation between feeding rate and nestling age, and between feeding rate and fledgling age, was significant. In contrast to nestlings, younger fledglings were fed at a higher rate than older ones.     

Cuckoo parasitism in a cavity nesting host: near absent egg‐rejection in a northern redstart population under heavy apparent (but low effective) brood parasitism

Brood parasite – host systems continue to offer insights into species coevolution. A notable system is the redstart Phoenicurus phoenicurus parasitized by the ‘redstart‐cuckoo’ Cuculus canorus gens. Redstarts are the only regular cuckoo hosts that breed in cavities, which challenges adult cuckoos in egg laying and cuckoo chicks in host eviction. We investigated parasitism in this system and found high overall parasitism rates (31.1% of 360 redstart nests), but also that only 33.1% of parasitism events (49 of 148 eggs) were successful in laying eggs into redstart nest cups. The majority of cuckoo eggs were mislaid and found on the rim of the nest; outside the nest cup. All available evidence suggests these eggs were not ejected by hosts. The effective parasitism rate was therefore only 12.8% of redstart nests. Redstarts responded to natural parasitism by deserting their nests in 13.0% of cases, compared to desertion rates of 2.8% for non‐parasitized nests. Our egg parasitism experiments found low rates (12.2%) of rejection of artificial non‐mimetic cuckoo eggs. Artificial mimetic and real cuckoo eggs added to nests were rejected at even lower rates, and were always rejected via desertion. Under natural conditions, only 21 cuckoo chicks fledged of 150 cuckoo eggs laid. Adding to this low success, is that cuckoo chicks are sometimes unable to evict all host young, and were more likely to die as a result compared to cuckoo chicks reared alone. This low success seems to be mainly due to the cavity nesting strategy of the redstart which is a challenging obstacle for the cuckoo. The redstart‐cuckoo system appears to be a fruitful model system and we suggest much more emphasis should be placed on frontline defences such as nest site selection strategies when investigating brood parasite–host coevolution.     

Developmental plasticity varied with sex and position in hatching hierarchy in nestlings of the asynchronous European roller,Coracias garrulus

Allocation rules between ornamental and other functional traits of birds may differ among individuals and vary with environmental conditions. We supplemented roller (Coracias garrulus) nestlings with methionine in a between‐nest design to investigate the way in which the sex and position in the hatching hierarchy affect the allocation of resources among growth, immunity, and plumage coloration. Methionine induces the production of lymphocytes at expense of growth; thus, we used it to manipulate growth and immunity, which are two traits likely to compromise plumage coloration. We predicted that late‐hatched chicks within a brood (juniors) compared to early‐hatched chicks (seniors) should allocate more to traits directly providing fitness than to ornamental traits because juniors are more affected than seniors by sibling competition. The methionine treatment effectively enhanced the production of lymphocytes in experimental broods. This appeared to be at the expense of plumage coloration in junior nestlings because, in supplemented nests, junior males showed a trend to display less greenish bellies than junior males from control nests. However, juniors from supplemented nests maintained wing growth as in control juniors. The plumage coloration of seniors was unaffected by the methionine supplementation, although they paid the costs of lymphocyte production at a level of growth that was reduced compared to senior nestlings in control nests. Hence, sex, and hatching order affected resource allocation among growth, immunity, and plumage coloration of roller nestlings. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 500–511.     

Incubation prior to clutch completion accelerates embryonic development and so hatch date for eggs laid earlier in a clutch in the great tit Parus major

The ability of parents to respond to changes in food supply within a season will have a large effect on fitness through the number and quality of chicks fledged. Great tits, Parus major, attempt to synchronise their production of chicks with a seasonal food peak, but when food supply fails, hatching asynchrony of chicks provides a mechanism by which some young can be fledged because more developed chicks outcompete their less developed siblings for the reduced parental food supply. We tested whether female great tits can potentially control the degree of hatching asynchrony by using incubation before clutch completion, so that early laid eggs develop faster and hatch sooner. The temperature of an artificial egg placed in 29 nests during the laying period was measured with data loggers, and nocturnal incubation of eggs similar to incubation post clutch completion was recorded in all nests. We then demonstrated that eggs removed from the nest for 72 hour periods prior to clutch completion hatched later than eggs remaining in the nest for the entirety of the laying period. Our results show that variable pre clutch completion incubation (which was mostly nocturnal) can lead to faster embryo development and earlier hatching, so potentially providing a mechanism for adaptive female control of degree of hatching asynchrony.     

Observations on the breeding biology and behaviour of the Lesser Jacana,Microparra capensis

Two Lesser Jacana nests were found in Hwange National Park, Zimbabwe and were observed over a period of four months beginning in March 2000. Both sexes were involved in preparing the breeding platform, incubation, and caring for the chicks, which were not carried by the adults. Both nests had three eggs. The incubation period for one clutch of eggs was not less than 19 days. The chicks all hatched on the same day and remained in the vicinity ofthe nest for the first few days where they were brooded by an adult. Initially the adults brought food to the chicks but the chicks started feeding themselves when they moved away from the nest. Ten days after hatching the chicks had doubled in size and were walking confidently with the attending adult some distance from the nest. First flight was seen at 32 days old, and the chicks appeared to be independent 63 days after hatching.     

Breeding biology of rooks (Corvus frugilegus L.) in Hawke's Bay,New Zealand

Abstract

Three rookeries in Hawke's Bay were studied during 1966–68. First or replacement clutches were started between 26 August and 23 October. First clutches averaged 4.3 eggs and replacements 3.7 eggs. The mean size of first clutches varied between years from 4.1 to 4.6 eggs. Incubation took 17–18 days. Most losses occurred around hatching, when about 40% of the eggs or young were lost. Incubated eggs and small nestlings incurred losses of 20% and 10% respectively, and all nestlings older than 10 days survived to at least 20 days. On average, 1.4 young were reared per nest in which eggs were laid; successful nests averaged 2.2 young. First clutches averaged 1.3 young (2.4 per successful first clutch). During the season, mean clutch size declined from 4.2 to 3.5, the mean number of young hatched declined from 2.0 to 0.6 per clutch, and the mean number of young fledged from all clutches declined from 1.3 to 0.4 per clutch. Mean nestling weight increased with age from 14 g on the first day after hatching to 360 g on the 19th day. The causes of egg and nestling mortality and the adaptiveness of clutch size are discussed.     

Experimentally Constrained Virulence is Costly for Common Cuckoo Chicks

Chicks of some avian brood parasites show high virulence by eliminating all host progeny in the nest whereas others develop in the presence of host nestmates. Common cuckoo ( Cuculus canorus ) chicks are typically highly virulent parasites as they attempt to evict all host eggs and chicks soon after hatching. However, several features of nest design, including steep walls and/or cavity nests, may effectively prevent cuckoo hatchlings from evicting nestmates. A previous observational study showed low success of cuckoo chicks in evicting progeny of a cavity nester host, the redstart ( Phoenicurus phoenicurus ) but cuckoo chicks showed low survival both when reared alone or in mixed broods with host nestmates. Whether poor cuckoo performance was caused by eviction costs and/or by the effect of presence of host chicks per se remains unclear. We experimentally cancelled any potential eviction costs by removing host eggs immediately after the cuckoo hatched and creating mixed broods 5 days later when the eviction instinct of the cuckoo already ceased. Cuckoos that were forced to compete with host nestlings experienced lower provisioning rates, poorer growth, and lower fledging success than control lone cuckoos. Cuckoos in mixed broods that survived until fledging fledged later, and at lower masses, than those in the sole cuckoo group. Thus, the cuckoo gens specializing on redstarts is similar to other cuckoo gentes, whose chicks are more successful in evicting host nestmates, and it does not benefit from the presence of host brood. Cohabitation with host nestlings then should be viewed as a maladaptive by-product of host cavity nest design.     

A molecular genetic analysis of the communal nesting of the ostrich (Struthio camelus)

The ostrich breeding system is complex and unique; communal clutches are laid by several females, although only one female, the major female, and the resident territorial male provide parental care. More eggs are laid in the nest than can be incubated and the major female ejects surplus eggs from the incubated central clutch. Microsatellite markers were used to analyse the parentage of communal nests in Nairobi National Park. This revealed that major females contributed a disproportionate number of fertile eggs to the central, incubated clutch and that multiple paternity and maternity within a nest were common; 68.9% of all incubated eggs on a nest were not parented by both the resident territorial male and the major female of that nest. All the males fertilized eggs on the clutches of neighbouring males. Unexpectedly, every major female with her own nest was also simultaneously a minor female with incubated eggs on neighbouring clutches. The relatedness between females laying in the same nest was not significantly different from the population average and significantly less than that between chicks hatched from the same nest.     

洋县野生朱Huan的繁殖

朱鹮(Nipponia nippon)的繁殖状况 ,尤其是种群数量的变化 ,一直受到国内外的关注。本文收集分析了 1 981～ 1 997年 1 7年朱繁殖资料 ,进一步研究了朱的繁殖及其数量 ,以期为朱保护 ,采取行之有效的措施 ,提供科学依据。1　研究方法自 1 981年朱被重新发现后 ,至 1 997年 ,每年3～ 6月繁殖期 ,固定人员 ,2～ 3人为 1组 ,在每个巢区设立观察点 ,进行跟踪观察 ,并详细统计每窝产卵数、孵化数、雏鸟成活数和死亡数。并结合平常的跟踪监护 ,调查分析种群数量动态 ,统计成鸟死亡数 ,然后进行整理分析。2　结果与讨论2 .1　种群数量1 98…     

Growth rate, size, and sex ratio of last-laid, last-hatched offspring in the tree swallow Tachycineta bicolor

In tree swallows Tachycineta bicolor, last‐laid eggs typically hatch one to two days after the other eggs in the clutch hatch, putting last‐hatched offspring at a disadvantage when competing for food delivered by parents. We studied the biology of last‐laid, last‐hatched tree swallow offspring over two years in a Wyoming, USA, population. Our first objective was to compare the growth of last‐hatched offspring to that of their earlier‐hatched nestmates. One previous study had suggested that last‐hatched, competitively disadvantaged offspring grow feathers faster than senior nestmates, even at the expense of other aspects of growth. This may allow last‐hatched offspring to fledge with senior nestmates and avoid abandonment by parents. A second objective was to determine the sex of nestlings from last‐laid eggs. If last‐laid eggs typically produce undersized, weak adults that are poor competitors for resources, and if the fitness costs of being undersized/weak are more severe for males than for females, then selection may favour having offspring from last‐laid eggs to be female. In this study, last‐laid eggs hatched in 63 of 66 (94%) nests and hatched last in 93% of cases. At hatching, offspring from last‐laid eggs weighed, on average, 63% as much as their three heaviest nestmates (range: 26–107%). Offspring from last‐laid eggs fledged from 71% of the nests that produced at least one fledgling and apparently starved to death in remaining nests. Last‐hatched offspring who were presumably at a substantial competitive disadvantage (those whose mass at hatching was no more than about 75% of the mean mass of their three heaviest nestmates), gained mass more slowly than their senior nestmates but they eventually attained the same peak mass before fledging. Last‐hatched offspring grew primary feathers more slowly than their senior nestmates although the difference in growth rate was slight (0.2 mm/d) and only marginally significant. As a group, offspring from last‐laid eggs did not differ from offspring from all other eggs in either maximum mass attained before fledging or tarsus length at fledging. This is atypical for species with asynchronous hatching and is possibly the result of another unusual trait: the tendency of parent tree swallows to distribute food equally among young within broods. The sex ratio of offspring from last‐laid eggs did not deviate from 1:1 (22 males, 21 females). Given that last‐hatched eggs do not routinely produce undersized/weak individuals in our study population, there should be little selection on parent females to bias the sex ratio of last‐laid offspring towards females.     

Blue penguin (Eudyptula minor) nest distribution and breeding success on Otago Peninsula, 1992 to 1998

Abstract

Annual counts of nests with eggs or chicks (known nests) were made at blue penguin (Eudyptula minor) breeding sites on the Otago Peninsula in each November from 1994 to 1997. Although the population has doubled to an estimated 600 known nests over this period, the number of breeding sites on the Otago Peninsula has reduced since the 1970s. Breeding success at three areas at Taiaroa Head were monitored by regular nest checks in the breeding season from 1992 to 1998. At Taiaroa Head reproductive success ranged from 41 to 78% at the three sites during the seven‐year study and was generally higher for pairs nesting in nest boxes than for those in burrows. The percentage of breeding pairs that laid a second clutch after fledging at least one chick from their first clutch (double brooded) varied between seasons (0–48%) and was correlated with the date of the onset of breeding. Egg loss, possibly through predation by Norway rats (Rattus norvegicus), influenced the significantly lower reproductive success at one area (Area A) at Taiaroa Head during the 1996 season.     

Breeding success of New Zealand falcons (

Productivity data on the New Zealand falcon (Falco novaeseelandiae) were collected from 87 nest sites in Kaingaroa pine plantation during three breeding seasons, 2003 to 2006. On average, 1.81 chicks were successfully fledged per nest, with young reared successfully at 71% of nests. Breeding occurred between August and March, with most eggs laid before December and most chicks fledged by February. Fifteen percent of nests were depredated, 9% contained eggs that failed to develop and 4% failed owing to forestry operations disturbing or destroying nests. No negative impact of 1080 bait or of desiccant or release spray application was recorded on falcon productivity. The population of falcons in Kaingaroa Forest increased during a period of pest control using 1080 bait so we see no reason to discontinue its use. Although impacts from forestry operations were low and restricted to land preparation and harvesting operations, there is potential for adverse impacts to increase. Mechanical forestry operations can continue without negative impacts by avoiding a buffer zone of 100?200 m around an active falcon nest.     

Hand-rearing,growth, and development of the red bird of paradise (Paradisaea rubra) at the New York Zoological Park

Growth and development of six hand-reared red bird of paradise chicks was documented at the New York Zoological Park from March 1988 to May 1989. A total of 16 eggs were laid, of which 10 were fertile. Clutches consisted of two eggs and the female left the next infrequently during incubation. Two chicks left in the nest were apparently victims of parental abuse. Eggs were subsequently removed from the nest after 10–14 days, candled, and if fertile, were artificially incubated. The average incubation period was 16.6 days. Newly hatched chicks were without down and their eyes remained closed until approximately 6 days of age. Hand-reared chicks were maintained in Air Shield Infant Isolettes. The weight of newly hatched chicks was about 8 g, and the weight typically doubled during the first week. Ratios of food intake to body weight were highest between day 4 and 10. Pin feathers were visible on the wings after 4 days, and after 3 weeks, the chicks were fully feathered. Analysis of the diet revealed acceptable levels of iron, but vitamin A and E levels were higher than recommended for poultry chicks. This paper documents the first successful hand-rearing of any species of birds of paradise from hatching to fledging.