THE LEVEL OF RESERVE PROTEIN AS THE PROXIMATE FACTOR CONTROLLING THE TIMING OF BREEDING AND CLUTCH-SIZE IN THE RED-BILLED QUELEA QUELEA QUELEA

Changes in the fat and flight muscle protein reserves of adult Red-billed Queleas Quelea quelea were followed in two colonies in Tanzania and Botswana. At the start of a breeding attempt the protein reserves were higher that at any other time of the year, particularly in females which had heavier flight muscles (non-fat dry weight) than did the (larger) males at that time. The pre-breeding increase in the labile component of the muscle protein (the actual protein reserve) is calculated at 80% for females, but only 14% for males. The fat reserve was only increased slightly at the beginning of the breeding attempt.
In both sexes, though for different reasons, the protein and fat reserves fell rapidly during the first few days of the attempt, in some individuals to dangerously low levels. During the incubation period there was rapid recovery while the situation during the rearing period appeared to vary between colonies.
It is proposed that the proximate control of breeding is provided by the individual's own body condition, and particularly the state of its protein reserves. No environmental releasers are required for the birds to breed at the appropriate time of the year.
Individual females producing two, three and four egg clutches differed in the rate at which their reserves fell during egg formation. The results are used to support the view that in this quelea the actual clutch-size produced on any occasion is the largest the female can produce before becoming too enfeebled. Thus, clutch-size appears to be determined phenotypically downward from a maximum which is indirectly under genetic control.     

THE TIMING OF BIRDS' BREEDING SEASONS

Examination of survival rdtes of nestlings and fledglings of some species show that there is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed. Since natural selection so strongly favours parents who leave many surviving young, the question arises as to why other birds breed later than the date at which they could most successfully raise their young.
It is suggested that the food supply for the breeding females immediately prior to the breeding season may limit their ability to form eggs and the females may thus not be able to lay at the time which would result in young being in the nest at the best time for raising them, but as soon after this time as the female is able to produce her eggs. Not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young and the groups of birds most likely to be affected are discussed.     

朱鹮(Nipponia nippon)的繁殖习性

文章概述了朱鹮的濒危状况及陕西省洋县1981—1986年的繁殖数量,计6年9窝27幼,已知死亡4只,人工喂养3只。 朱鹮在洋县为留鸟,越冬期间偶尔返回繁殖地,2月中旬后不再离开。有显著的领域性。3月上旬开始营巢,中旬至4月初产卵,多数3枚(1—4枚)。孵卵期30天左右,育雏期约为40天,均由雌雄亲鸟共同承担。6月中下旬全窝育成后一起飞离巢区。     

The presence of kleptoparasitic fledglings is associated with a reduced breeding success in the host family in the barn owl

Fledgling birds sometimes abandon their own nest and move to neighboring nests where they are fed by host parents. This behaviour, referred to as ‘nest‐switching’, is well known in precocial birds that are mobile soon after hatching and can easily reach foster nests. In contrast, due to the difficulty of observing nest‐switching in territorial altricial birds, the causes and consequences of moving to others’ nests are poorly known in this group of birds. Nest‐switchers can be adopted by the foster parents or they can steal food from the host parents meant for their offspring, a form of kleptoparasitism, which may result in reduced breeding success of the host nest. In Israel, 12 barn owl fledglings left their natal nests and were found in 9 host nests out of 111 monitored nests (8.1%). Nest‐switchers that fledged earlier in the breeding season flew shorter distances to reach host nests probably because the density of nests with younger nestlings is higher early in the season. The number of host nestlings fledged and the percentage of nestlings fledged was lower in host nests than in nests without switchers. The occasional nest‐switchers were always older than host nestlings (respectively 80 and 50 days of age, on average) and host parents fledged fewer young when nest‐switchers occupied host nests with younger nestlings. This suggests that nest‐switchers are kleptoparasites because the presence of the older alien fledglings is associated with a lower breeding success of the host parents.     

Brood-parasitism by the Shining Cuckoo Chrysococcyx lucidus at Kaikoura, New Zealand

For three seasons starting in 1976 I studied the breeding of Shining Cuckoos Chrysococcyx lucidus in forest near Kaikoura, New Zealand. There is no evidence that the cuckoo parasitizes any host on mainland New Zealand other than the Grey Warbler Gerygone igata. A nestling cuckoo returned to within 1 km of its natal site in a subsequent breeding season, presumably after migrating beyond New Zealand. Empirical and theoretical estimates of the area occupied by Shining Cuckoos while breeding are given. Cuckoos near Kaikoura laid during ten weeks, the modal week of laying following seven weeks after the presumed peak of arrival of birds in New Zealand. First clutches of the host escaped parasitism because they were laid before most cuckoos arrived. Parasitized clutches received one cuckoo egg which replaced a host's egg. It was laid before, just after or long after the host began incubating, and mimicry was lacking. Cuckoo eggs, which were about 8% of the adult cuckoo's weight, hatched in 14–17 days. The frequency of parasitism near Kaikoura was 55% of late clutches (n = 40).
At 3–7 days old, nestling Shining Cuckoos evicted from the nest all other contents. The nestling period was at least 19 days. Growth in weight followed a logistic curve and the equation is given. Just over half the cuckoo eggs produced fledglings. The effect of brood-parasitism on the Grey Warbler's productivity was small. Only 17% of late warbler eggs, and late eggs only, were prevented by parasitism from yielding fledglings. Late laying by some Shining Cuckoos (relative to the host's incubational cycle), and late eviction, often led to brief inter-specific competition among nestlings for food. The brief coexistence of young Warblers and Cuckoos in the nest may explain the apparent mimicry by newly-hatched Shining Cuckoos of the host's young.     

THE BIOLOGY OF OYSTERCATCHERS HAEMATOPUS OSTRALEGUS ON SKOKHOLM ISLAND, S. WALES

A population of about 50 pairs of Oystercatchers Haematopus ostralegus nesting on Skokholm Island, S. Wales, was studied between 1963 and 1965. Other information on Skokholm Oyster-catchers over the last 25 years was also analysed.
The adults were trapped, colour-banded and sexed by bill measurements. With few exceptions, birds kept the same mates and territories from one season to the next. Apparently the male is responsible for retaining the territory. Some Oystercatchers breed at three years but most do not do so until four or five. It seems that there is a high population pressure, preventing young birds from establishing themselves. The annual adult survival in the two years was 88% and 90% respectively.
The average clutch-size on Skokholm is known for many years, and varied annually between 2^.5 and 3.3. The number of c/4 varied greatly from year to year. There was a seasonal decline in mean clutch-size and also in egg and nest success. Predation, especially by Lesser Black-backed Gulls, was the main cause of egg loss.
In 1963, 36.7% of hatched chicks fledged and 59% in 1964. The larger clutches were more successful and produced more surviving young than did the more numerous smaller clutches. Early hatched young are more successful than later young.
The average yearly mortality of birds between fledging and breeding was 40%.     

THE CHARACTERS OF A NEW RACE OF Alcedo semitorquata Swainson FROM THE LOW COUNTRY OF PORTUGUESE EAST AFRICA

Arkell, G. B. F. 1979. Aspects of the feeding and breeding biology of the Giant Kingfisher. Ostrich 50:176-181.

Giant Kingfishers Megaceryle maxima were studied during 1972–1975 on the Eerste and Blaauwklip Rivers near Stellenbosch (33 53s; 18 50E), South Africa. Nest record cards of the Southern African Ornithological Society were examined for dimensions of the nest, nest lining, clutch-size and brood-size. The feeding rate of nestlings was determined from observations at the nest. Two adults, comprising a pair of breeding birds, and a fledgling wert equipped with breast-mounted miniature radio transmitter packages to monitor the birds activity and home range. Cape River Crabs Potamon perlatus apparently were the main prey of the kingfishers. A correlation was found between the activity patterns of kingfishers and of crabs, which peaked in the mornings and evenings.     

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.     

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.     

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…     

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).     

Incubation temperature impacts nestling growth and survival in an open‐cup nesting passerine

For oviparous species such as birds, conditions experienced while in the egg can have long‐lasting effects on the individual. The impact of subtle changes in incubation temperature on nestling development, however, remains poorly understood, especially for open‐cup nesting species with altricial young. To investigate how incubation temperature affects nestling development and survival in such species, we artificially incubated American robin (Turdus migratorius) eggs at 36.1°C (“Low” treatment) and 37.8°C (“High” treatment). Chicks were fostered to same‐age nests upon hatching, and we measured mass, tarsus, and wing length of experimental nestlings and one randomly selected, naturally incubated (“Natural”), foster nest‐mate on days 7 and 10 posthatch. We found significant effects of incubation temperature on incubation duration, growth, and survival, in which experimentally incubated nestlings had shorter incubation periods (10.22, 11.50, and 11.95 days for High, Low, and Natural eggs, respectively), and nestlings from the Low treatment were smaller and had reduced survival compared to High and Natural nestlings. These results highlight the importance of incubation conditions during embryonic development for incubation duration, somatic development, and survival. Moreover, these findings indicate that differences in incubation temperature within the natural range of variation can have important carryover effects on growth and survival in species with altricial young.     

The breeding biology of the Scimitarbilled Woodhoopoe

Steyn, P. 1999. The breeding biology of the Scimitarbilled Woodhoopoe. Ostrich 70 (3&4): 173–178.

The breeding biology of the Scimitarbilled Woodhoopoe Rhinopomastus cyanomelas was studied at two sites in Zimbabwe over a 13-year period from 1964–1977. The pairs were resident, remained together throughout the year, and inspected their nest sites occasionally during the non-breeding season. The breeding season extended from August to December with a marked September/October peak. Eggs were laid at daily intervals. Clutch size averaged 2.9 (range 2–4). Incubation began either with the penultimate or last laid egg. During the 13–14 day incubation period the female left the nest only occasionally each day and was reliant on the male for food. This pattern continued for four days after the chicks hatch. Thereafter she started to forage and gradually increased her contribution to chick provisioning until she overtook that of the male. With one exception, he never fed the chicks directly and delivered the food to the female. The nestlings were brooded overnight for the first two weeks. The anti-predator response of the young included a malodorous brown exudation from the preen gland and unpleasant liquid excreta. The nestling period was 21–24 days and the young left the vicinity of the nest with their parents and did not return to roost in it. Twelve breeding cycles were monitored and 76% of eggs laid (n=37) produced fledged young. Second broods were raised in the same nest on two occasions after successful rearing of the first, presumably by the same pair, but the birds were not individually marked. There was no evidence of helpers at the nest.     

绿鹭的繁殖习性观察

2001年4－9月在合肥市对绿鹭（Butorides striatus)的繁殖习性进行了观察。绿鹭营巢生境主要选择在建筑物附近的高大阔叶树上,常一树一巢,未见与其他鹭类混群营巢。每巢产3－5枚卵,孵卵期21d,育雏期41d,42日龄后幼鸟离巢飞走,出飞存活率62．5％。育雏期雏鸟主要食物为小型鱼类。在4所大学校园及1处公园统计到有效巢56个,推算绿鹭224只。绿鹭在合肥繁殖属首次记录。     

Predation risk is unlikely to account for the failure of subordinate speckled warblers Chthonicola sagittata to help at the nest

The predator avoidance hypothesis suggests that the failure of subordinate birds to provision nestlings in communally breeding species is a consequence of increased predation risk. Parents exclude subordinates from the nest area and thus reduce the frequency of predator-attracting visits when the nest is most vulnerable, leading to increased reproductive success. I evaluated this hypothesis for the speckled warbler Chthonicola sagittata , a group-living member of the Pardalotidae in which subordinate males never feed nestlings or fledglings even though they are unrelated to the primary pair, compete for copulations and sometimes sire young in the brood. Parents did not modify provisioning behaviour relative to the risk of nest predation; provisioning rates to 10 d-old nestlings were similar on high and low risk territories. Furthermore, there was no evidence that parents modified the timing of deliveries or adjusted the relative size of deliveries in relation to predation risk. The condition (residual mass) of nestlings differed between high and low risk territories because nestlings on high risk territories had smaller tarsi but similar body mass to those at low risk. Tarsus length was the result of parental phenotype, not modified provisioning behaviour. Given that parents were unresponsive to predation risk, it seems unlikely that predation can account for the failure of subordinates to provision at the nest.     

The cost of incubation in relation to clutch-size in the Collared Flycatcher Ficedula albicollis

This study examines the importance of avian incubation costs as determinants of clutch-size variation by performing clutch-size and brood-size manipulations in the same population of Collared Flycatchers Ficedula albicollis during the same breeding season. In 2 5 cases when three or more clutches of the same size were completed on the same day, we moved two eggs on the day after the last egg had been laid from one randomly selected clutch (C) to another (C) and moved two other eggs from this to a third clutch (C⁺). In 20 other cases of simultaneously completed clutches of the same size, we moved two randomly selected young from one brood to a second and from that moved two other young to a third (B, B and B⁺groups). Most females were weighed the day after completion of the clutch and 1–4 days before hatching of the young, and some of them also 10–14 days after hatching of the young. We measured the daily energy expenditure of females incubating manipulated clutches of 4, 6 and 8 eggs by means of the doubly-labelled water (D₂¹⁸O) technique and also recorded their nest attendance. Hatching success of fertilized eggs was reduced in the enlarged clutches compared with control and reduced clutches. Females expired on average 3142.6 ml CO₂ and expended 78.6 kJ per day while incubating, which corresponds to a metabolic intensity of 3.3 times BMR. Daily energy expenditure increased with clutch-size due to higher costs while incubating, and not because of changed activity patterns. There were no significant differences in length of incubation, female mass or mass changes between phases for the C, C and C⁺groups. In both the C and B groups, enlarged broods produced significantly more fledged young than control broods, and those significantly more than reduced broods. Fledgling tarsus-length and mass did not differ significantly between treatments in either the C or B groups. There was no significant difference in breeding success between clutch and brood manipulations. In this season, incubation costs did not entail significant fitness losses, expressed either as fledgling production or female condition. Also, control females could have raised more young to fledging age than they did with no apparent costs.     

SUPPLEMENTARY OBSERVATIONS ON THE BREEDING BIOLOGY OF THE BOOTED EAGLE IN SOUTHERN AFRICA

Steyn, P. & Grobler, J. H. 1985. Supplementary observations on the breeding biology of the Booted Eagle in Southern Africa. Ostrich 56:151-156

Further observations on the biology of the Booted Eagle Hieraaetus pennatus in southern Africa are presented. Several nest sites in trees are described, and details of behaviour during the incubation and early nestling period are given. The down colour of nestlings is discussed. One juvenile returned to its natal area the following breeding season. In ninepair-years the replacement rate was 1,0 young/pair/year. Prey records confirm that birds predominate. The implications of the recent discovery of breeding in mid-winter in Namibia are discussed; there may be three Booted Eagle populations in southern Africa.     

BREEDING OF THE GREY WARBLER GERYGONE IGATA AT KAIKOURA, NEW ZEALAND

I studied the breeding of Grey Warblers Gerygone igata (Muscicapidae: Acanthizinae) in forest near Kaikoura, New Zealand, between 1976 and 1979. Only males sang and singing occurred all year. From late July to January pairs defended self-contained territories of 0·25–1·73 ha but they occupied larger home ranges when not breeding. Territorial adults were strictly sedentary all year. The average annual mortality of breeding adults was 18·5% and the predicted life-expectancy 4·9 years, which is remarkable in a bird weighing 6–7 g. The breeding season from first building to last fledging was six months long and it began early. Exceptionally, Grey Warblers may build and lay before the shortest day. As the season progressed warblers nested lower on average, both in absolute terms and relative to the tree nested in and canopy at the site. Warblers built in 7–27 days then delayed up to eight days before laying. Only females built and at no stage of breeding did males feed their mates. Both sexes fed the young. Grey Warblers laid for 15–16 weeks of the year and first clutches were laid asynchronously during 5–6 weeks. Eggs of a clutch appeared at two-day intervals and each egg weighed 1·5 g when fresh (23% of mean adult weight). Clutch size was nearly constant (mean 3·9, mode 4, range 3–5). The incubation period was 17–21 days (mean 19·5 days) and the nestling period 15–19 days (mean 17·2 days). On average the clutch hatched over 1·4 days, even though incubation commenced with the laying of the last egg. Nestlings reached maximum weight on Days 13–14 on average and then receded in weight by 4%, apparently through loss of water. All healthy nestlings exceeded mean adult weight during development by up to 39%. Nestlings from broods of two were at first lighter on average than those from larger broods, but in the second half of the nestling period twins were significantly the heaviest. Grey Warblers were fed for 28–35 days after fledging and they survived well while dependent on parents. Fledglings dispersed up to 3 km or more at independence and only 5% per annum joined the breeding population. Of nests that received eggs, 42% produced at least one fledgling. On average each breeding adult raised 2·0 fledglings per season. Of 265 eggs in 73 nests 70% hatched and 38% produced fledglings. Of 185 nestlings 54% fledged. Probably the main cause of mortality of eggs and nestlings was predation by introduced rodents and mustelids. Grey Warblers raise two small broods slowly during a long breeding season, rather than investing in one large quickly-reared brood. In New Zealand's mild climate the warbler's food supply may not decline severely in winter, and the population of warblers may remain so close to the limit set by food that extra for breeding is hard to obtain. Thus the breeding strategy may be adapted to a restricted food supply.     

The reproductive biology of the Red Shining Parrot Prosopeia tabuensis on the island of 'Eua, Kingdom of Tonga

On Eua, Red Shining Parrots Prosopeia tabuensis breed in the cool and dry season, i.e. from May to October. Climate is the main factor timing the breeding season, which gives additional evidence for an assumed origin of the genus from temperate regions. Two or three eggs are laid in cavities of forest trees; the incubation time is about 24 days. Only females were observed brooding and feeding the young. Nestlings were fed three times a day independently of age. Single nestlings and older siblings received almost twice as much food per feeding as younger siblings. Growth constants are presented for weight, the width of the upper mandible, and wing-length. The fledging age is reached after 7 weeks but none of the observed nests fledged young due to predation by man. Breeding success was calculated at more than 50% for those nestlings that would have fledged without human interference. The reproductive biology of the Red Shining Parrot does not, apparently, show island-specific adaptations such as a reduced clutch-size or a prolonged nestling period.     

THE BIRDS OF LANGEBAAN LAGOON

Data are presented on breeding success of Red Bishops (Euplectes orix) collected over four breeding seasons at a colony in the Addo Elephant National Park, Eastern Cape, South Africa. Overall hatching and fledging success were 53.8% and 26.0% of all eggs laid, respectively, and the overall mean number of fledglings per breeding attempt was 0.77. Hatching and fledging success varied significantly among seasons, with both clutch and brood losses due to predation being the main reason for the observed differences. Hatching success also differed significantly among clutch sizes, being highest for four-egg clutches (63.2%), intermediate for three-egg clutches (55.5%) and lowest for two-egg clutches and five-egg clutches (33.2% and 34.3%, respectively). However, fledging success was not significantly different among clutch sizes. The mean number of fledglings per breeding attempt was 0.44 for two-egg clutches, 0.80 for three-egg clutches, 1.10 for four-egg clutches, and 0.57 for five-egg clutches. The height of accepted nests (i.e.nests in which at least one egg was laid) was significantly lower than the height of nests not accepted. In addition, accepted nests in which eggs hatched and young fledged were significantly lower than accepted nests in which no eggs hatched and no young fledged. These overall effects of nest height on nest acceptance and hatching and fledging success were, however, due only to nests built above water, since no such effects were found when nests built above ground (i.e.on dry land) were analysed separately. I detected no effect of nest coverage on the probability of a nest being accepted, nor was there any effect of nest coverage on hatching or fledging success. Nests above water were significantly more likely to be accepted than nests above ground; however, hatching and fledging success of nests that were accepted did not differ significantly between nests built above water and those built above ground.