Imperfect mimicry of host begging calls by a brood parasitic cuckoo: a cue for nestling rejection by hosts?

Coevolutionary interactions between avian brood parasites and their hosts often lead to the evolution of discrimination and rejection of parasite eggs or chicks by hosts based on visual cues, and the evolution of visual mimicry of host eggs or chicks by brood parasites. Hosts may also base rejection of brood parasite nestlings on vocal cues, which would in turn select for mimicry of host begging calls in brood parasite chicks. In cuckoos that exploit multiple hosts with different begging calls, call structure may be plastic, allowing nestlings to modify their calls to match those of their various hosts, or fixed, in which case we would predict either imperfect mimicry or divergence of the species into host-specific lineages. In our study of the little bronze-cuckoo (LBC) Chalcites minutillus and its primary host, the large-billed gerygone Gerygone magnirostris, we tested whether: (1) hosts use nestling vocalizations as a cue to discriminate cuckoo chicks; (2) cuckoo nestlings mimic the host begging calls throughout the nestling period; and (3) the cuckoo begging calls are plastic, thereby facilitating mimicry of the calls of different hosts. We found that the begging calls of LBCs are most similar to their gerygone hosts shortly after hatching (when rejection by hosts typically occurs) but become less similar as cuckoo chicks get older. Begging call structure may be used as a cue for rejection by hosts, and these results are consistent with gerygone defenses selecting for age-specific vocal mimicry in cuckoo chicks. We found no evidence that LBC begging calls were plastic.     

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.     

BREEDING BIOLOGY OF THE MANX SHEARWATER PUFFINUS PUFFINUS

Studies on the breeding biology of Puffinus puffinus were carried out in 1963 and 1964 at the large colony on Skokholm, Wales. During the six weeks before laying the birds spent up to a quarter of the days in the burrows, but the ten days immediately prior to laying were normally spent at sea. There is a prolonged laying period, with a marked peak in the first half of May. Details are given of a second egg being laid when the first was deserted immediately after being laid. The male took the first incubation spell. The incubation spells ranged from one to 26 days and averaged six. The incubation period was about 51 days. The frequency of visits to land by breeding birds, unlike those by non-breeders, was not affected by the moon. On hatching, the chicks grew rapidly and reached maximum weights of between 505 and 755 gm. sometime between 39 and 61 days. There was a variable desertion period, usually eight or nine days, before the chicks left the island about 70 days after hatching. During the feeding period the chick received about two feeds every three days. There is evidence that adults visited the chicks more frequently than this. There was no correlation between growth of the chicks, their feeding rates or fledging weights and the time of laying. There was a high survival (about 95 %) of chicks during the fledging period but some eggs were lost in disputes for burrows. Nine pairs in 1964 were unable to raise two young simultaneously. Parents altered their feeding rhythms to try to feed two young but did not themselves lose weight. It is suggested that the critical factor in the production of young is the availability of food for the young immediately after they leave the colonies.     

Sexual imprinting and the origin of obligate brood parasitism in birds

We discuss two pathways along which obligate brood parasitism (OBP) may evolve and examine some of the critical steps that must be passed by letting great tits Parus major be reared by blue tits Parus caeruleus in a field experiment. The cross-fostered chicks survived well in blue tit nests, but their local recruitment and reproductive success was much lower than that of controls. The effect was strongest when great tits grew up with siblings of the host species rather than with conspecific siblings in blue tit nests. The low success seemed to be caused by misimprinting because the cross-fostered birds behaved like blue tits in several aspects (species association, alarm calls, and aggressive response by resident females to caged intruders). Some birds of both sexes were apparently so strongly imprinted that they did not attract or accept a social mate of their own species. We conclude that imprinting may be necessary for OBP to evolve in birds because the parasite must be attracted to the nests of the host species to add eggs and thereby continue the parasitic life cycle. However, strong imprinting may also prevent OBP from occurring if parasitic offspring seek a mate from the host species.     

THE BREEDING ECOLOGY OF ROYAL TERNS STERNA (THALASSEUS) MAXIMA MAXIMA

The breeding ecology of the New World race of the Royal Tern Sterna maxima maxima was studied at colonies in Virginia and North Carolina, U.S.A., from 1967 to 1970. Colony sites are quite varied, but isolation, good distance visibility and (especially) freedom from quadruped predators seem important if not essential prerequisites. In Virginia, most adults arrive at the colony site in the last few days of March. Courtship, displaying and copulation take place at, near, and some distance from the colony site. In this the Royal Tern differs from its near relative S. sandvicensis sandvicensis which carries out these activities away from the colony site, presumably as an anti-predator device. Courtship displays are not described, but in their essentials are similar to those of other terns. Copulations continue throughout incubation and gradually disappear when the eggs hatch. No post-copulatory displays are known. Some synchrony of egg-laying is evident, but no “mass laying” occurs, the colony increasing in size steadily over a period of weeks and months. Defaecation on the nest is normal and probably serves to strengthen the nest rim against flooding by high tides. Contrary to published reports, the normal clutch is one; the largest is two, probably often from two different females. All incubating adults examined had two brood patches. Average egg measurements are 63 × 44-5 mm, and average egg weight is 64.3 g. Egg colour varies greatly, and evaluation is difficult. Eggs are probably not cryptically coloured and individual variation, as well as nest-site, are used by returning adults to identify their own eggs. Average maximum nest density is c. 7/m². Sterna sandvicensis acuflavida nests regularly, if not obligatorily, with m. maxima; interactions between the two, and possible benefits accruing to each, are discussed. Unhatched eggs were significantly nearer other nests than were successfully hatched eggs, and possible explanations are given. Incubation lasts about 30–31 days, a week longer than in most terns; both sexes incubate. Broken eggshells are never removed by the adults. Instead, after 2–3 days, the chicks leave the nest permanently to join a creche that roams freely about the immediate vicinity of the colony. Chicks remain in the creche for about 25–30 days, leaving it at fledging, approximately 30 days after hatching. While in the creche, chicks are normally fed only by their parents, who probably recognise them both vocally and visually, using the extensive variation in voice and colour of chicks characteristic of the species. Sandvicensis acuflavida chicks also are highly variable, and join Royal creches, adults of both species attending. Variation also occurs in Royals' juvenal plumage, and seems associated with extended parental care. Feeding adults normally wander up to 40 km from their colony, and this probably facilitates the intercolonial exchange of breeding birds we recorded. They feed inshore, in shallow waters, taking small fish by dives which do not go below the surface. They regularly take small soft-shell crabs in this way, and frequently water-skim like skimmers Rynchops spp., sometimes capturing food while doing so. A relationship between crab capture and water-skimming is established for the first time, and water-skimming in non-feeding contexts is mentioned. Besides the quadruped predators which they normally avoid by fleeing the colony site, Royals have no known predators beyond the egg stage. Eggs, although not chicks, are readily taken by Laughing Gulls. Relationships between the two species are discussed, emphasising their constant association the year round.     

Captive breeding for reintroduction: influence of management practices and biological factors on survival of captive kaki (black stilt)

An important component of the restoration strategy for the critically endangered kaki or black stilt (Himantopus novaezelandiae) is captive breeding for release. Since 1981 1,879 eggs were collected from wild and captive pairs, with birds laying up to four clutches. Eggs were incubated artificially and most chicks reared by hand until released as juveniles (about 60 days) or sub‐adults (9–10 months). Because survival in captivity is a significant determinant of the number of birds available for release, we wished to identify sources of variation in mortality to assess potential impacts of management on productivity. Hatchability was 78% for captive‐laid eggs and 91% for wild‐laid eggs. Survival of hatched eggs was 82% by 10 months of age for both wild and captive birds. Most egg mortality occurred early in incubation and around hatching: the timing of mortality was unaffected by whether birds were captive or wild, hybrid or pure kaki, or when eggs were laid. Heavier hatchlings showed higher initial survival, as did chicks from wild parents. Hatchlings from fourth‐laid eggs showed lowest survival, even though hatchling mass tended to increase with hatch order. Survival of chicks subjected to major health interventions was 69% after 4 months. No differences in survival were found between different genders, hybrids and pure kaki, hand‐reared or parent‐reared birds, chicks hatching early or late in the season, different seasons, different‐sized groups of chicks, chicks reared in different brooders, juveniles kept in different aviaries, and chicks from subsequent clutches. Birds subjected to minor health interventions were equally likely to survive as healthy chicks (82%). Survival was high despite aggressive management (quadruple clutching and collecting late in the season). Differences between captive and wild birds suggest further improvements could be made to captive diet. Wide variation in hatchability between parent pairs substantiates the practice of breaking up poorly performing pairs. Zoo Biol 0:1–16, 2005. © 2005 Wiley‐Liss, Inc.     

A brood parasite selects for its own egg traits

Many brood parasitic birds lay eggs that mimic their hosts'' eggs in appearance. This typically arises from selection from discriminating hosts that reject eggs which differ from their own. However, selection on parasitic eggs may also arise from parasites themselves, because it should pay a laying parasitic female to detect and destroy another parasitic egg previously laid in the same host nest by a different female. In this study, I experimentally test the source of selection on greater honeyguide (Indicator indicator) egg size and shape, which is correlated with that of its several host species, all of which breed in dark holes. Its commonest host species did not discriminate against experimental eggs that differed from their own in size and shape, but laying female honeyguides preferentially punctured experimental eggs more than host or control eggs. This should improve offspring survival given that multiple parasitism by this species is common, and that honeyguide chicks kill all other nest occupants. Hence, selection on egg size in greater honeyguides parasitizing bee-eaters appears to be imposed not by host defences but by interference competition among parasites themselves.     

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.     

THE SOCIABLE WEAVER,PART 3: BREEDING BIOLOGY AND MOULT

Maclean, G. L. 1973. The Sociable Weaver, Part 3: Breeding biology and moult. Ostrich 44: 219–240.

Rain or some associated phenomenon is the principal Zeitgeber releasing breeding in the Sociable Weaver. The species does not breed in the absence of rain. The same nest chambers are used for breeding as are used for roosting throughout the year. The Sociable Weaver is monogamous. The clutch size varies from two to six eggs, larger clutches being more common after good rains than in relatively poorer breeding periods. Food supply may therefore be the proximate factor regulating clutch size. Replacement clutches are not necessarily smaller than first clutches. The mean clutch size within a breeding period decreases with an apparent decrease in food supply. The parents share parental duties about equally. Up to four successive broods may be raised in a single breeding period; a breeding period may last up to nine months and may occur at any time of the year according to the somewhat erratic rainfall which averages about 226 mm per year in the study area.

First broods help their parents to feed later broods; fourth brood chicks may therefore be fed by as many as 11 birds (nine young and two parents). This has survival value especially toward the end of a breeding period when food is scarce. Of similar value is the habit of starting incubation with the first or second egg of the clutch; in a relatively poor season older chicks will survive while younger ones will starve, thereby effectively and quickly reducing brood size. Young birds moult into adult plumage at four months, but do not normally leave the home colony. The sexes are indistinguishable at all ages, but there is an approximate ratio of eight males to five females in the study area.

Wing moult is slow: each remex takes about a month for replacement. Body moult occurs within the space of a month, usually after rain while the birds are breeding. Primary remiges are moulted proximo-distally from 1 to 9; secondaries are moulted disto-proximally from 1 to 6. Body moult is antero-posterior with the dorsal surface slightly in advance of the ventral surface.     

Breeding ecology of Red‐faced Cormorants in the Pribilof Islands,Alaska

ABSTRACT Red‐faced Cormorants (Phalacrocorax urile) are North Pacific endemics recognized as a vulnerable species, but little is known about their breeding ecology. We studied Red‐faced Cormorants on St. Paul Island, Alaska, from 1975 to 2009, with more detailed data collected in 2004 and 2005. Mean clutch sizes in 2004 (3.2 ± 0.8 [SD] eggs) and 2005 (3.1 ± 0.8 eggs) were similar to the long‐term average (2.9 ± 0.3 eggs from 1976 to 2009). The mean laying interval in 2004 and 2005 was 2.15 ± 0.80 d (N= 407), and the mean egg period (number of days between laying of an egg and hatching) was 31.1 ± 1.4 d (N= 158). Approximately 64 ± 17% of eggs hatched during the period from 1975 to 2009. The mean number of chicks per nest in 2004 and 2005 was 2.8 ± 0.8 (N= 232), and the mean number of fledglings per initiated nest in all years was 1.22 ± 0.52. Chicks fledged 46 to 66 d posthatching. In 2004 and 2005, the primary causes of egg loss were predation by Arctic foxes (Vulpes lagopus) and destruction of eggs and abandonment of nests due to storms. Starvation was the primary cause of nestling mortality in both years. Because chicks are dependent on parents to provide food for over 45 d, consistent near‐shore foraging opportunities must be available. From 1975 to 2009, Red‐faced Cormorants experienced only 1 yr of complete reproductive failure (1984). The consistent reproductive success of Red‐faced Cormorants suggests that conditions may be relatively stable for this species on St. Paul Island, or that the variability in their breeding ecology (e.g., phenology, clutch sizes, and incubation strategies) provides the flexibility needed to successfully fledge some chicks nearly every year.     

Annual variation in breeding biology of gentoo penguins, Pygoscelis papua, at Bird Island, South Georgia

The breeding biology of the gentoo penguin, Pygoscelis papua , was studied over a three-year period (1986–1988) at Bird Island, South Georgia, with particular reference to birds of known age or breeding experience. Laying date varied significantly between all three years, being three weeks later in 1987, when the breeding population decreased markedly. Factors involved in the timing of breeding are discussed. Within years egg-laying was highly synchronous: 95% of clutches were initiated in 14·5 days or less. The incubation period was 35 days and the laying interval, between the two eggs, 3·3–3·4 days. Chicks creched when 25–30 days old, and this varied between years, possibly related to food supply and chick growth. Chicks left the colony for the first time between 75 and 85 days of age. The breeding population at Bird Island decreased by 20% and increased by 84% in successive years during the study period. Breeding success (chicks fledged per egg laid) varied between 0·33 and 0·65 within colonies, but for the whole island was very consistent over the three years: 0·45, 0·51 and 0·47. Overall, colony differences were not correlated between years. Disturbance from Antarctic fur seals, Arctocephalus gazella , is suggested as the cause of consistently lower breeding success at one colony. Mean egg weight varied annually, and with age of the breeding bird, nest location and, in one year, with laying date. Young, first-time breeders laid smaller eggs and had lower breeding success compared to older, experienced birds, similar to other seabirds. However, they differed from other species in laying on average earlier than older birds. The relationship between age, egg weight, laying date and breeding success is discussed in relation to predation and seasonal food supply.     

An investigation into egg-acceptance by azure-winged magpies and host-recognition by great spotted cuckoo chicks

Tests using magpie's eggs (which are very similar to those of the great spotted cuckoo) on azure-winged magpies (Cyanopica cyanea) showed that the latter accept strange eggs, rejecting only 25% of them. We therefore suggest that they are an accepter species, and as such a substitute host species for the great spotted cuckoo (Clamator glandarius). We suggest a theory for the transition from ‘Accepter Species’ to ‘Non-mimetic-egg Rejecter Species’ by hosts of specialist brood parasites. We have obtained evidence of host recognition by great spotted cuckoo chicks of typical or atypical host species characteristics. Basing our theory on the calls of parasitic chicks reared in the nests of the azure-winged magpies and magpies (Pica pica), we suggest that the foregoing is the mating mechanism necessary for the parasitization of a new host species.     

FOOD AS A FACTOR CONTROLLING THE BREEDING OF PUFFINVS LHERMINIERI

A study of Puffinus Iherminieri on Plaza Island, Galápagos, showed that, although eggs were laid in all months, there were marked peaks and troughs of laying. Intervals between successive layings varied with the success or failure of the first egg, an average of nine months for successful pairs, eight months for pairs which lost a young, and 6–5 months for those which failed to hatch an egg. However the breeding success did not influence the time between the end of one breeding attempt and the next laying. This suggests that birds were breeding as quickly as possible. The critical factor preventing more frequent breeding appeared to be the time required to replace the wing and tail feathers.
Details are given of the breeding biology, all aspects of which were strongly influenced by frequent and unpredictable food shortages. The average incubation period was 49 days but this was prolonged by temporary desertion due to food shortages. Chick growth and fledging periods (62 to 100 days) were variable. There was no well–defined desertion period and birds were experimentally induced to feed young for up to 120 days.
Overall nesting success was low (26%) and adult survival between breeding attempts was high (92–95%).
Food, planktonic fish larvae and Crustacea, appeared to be rarely abundant and details are given of the effect of food shortage on the breeding.
The breeding synchrony was brought about by food shortages. The ultimate factor controlling breeding appeared to be the availability of food for egg formation and there was no possibility of birds timing breeding so that young were being fed at a time of food abundance.
A comparison is made of the breeding of eight Puffinus species.     

Developmental plasticity in a passerine bird: an experiment with collared flycatchers Ficedula albicollis

Young birds often face poor food supply, which reduces their growth and development. However, if the shortage of resources is only temporary, there is a possibility to adjust the growth trajectory of morphological traits after the end of the short-term limitation period. The two main ways of compensatory growth are delayed development (parallel growth) and growth acceleration (catch-up growth). Parallel growth has been widely demonstrated in birds, but the presence of catch-up growth in altricial species has been questioned. However, most experiments have been conducted in laboratory conditions. We manipulated the food supply of nestling collared flycatchers Ficedula albicollis in the wild by removing the male parent for three days at 4–7 days of chick age. We performed early partial swapping to control for origin effects on growth, and total swapping after the period of food limitation to ensure similar late growth environment for deprived and control chicks. Both body mass and tarsus length of deprived chicks was negatively affected by the food scarcity. Body mass showed efficient catch-up growth, but this compensation was absent in skeletal size. Body mass is an important determinant of postfledging survival in this long-distance migrant. Further studies are needed in a variety of species to examine developmental plasticity in relation to age at food scarcity and the allocation hierarchy of various morphological traits.     

The Storm's Stork Ciconia stormi in Indonesia: breeding biology, population and conservation

Storm's Stork Ciconia stormi is one of the rarest of the storks, regarded as globally endangered and found only in parts of western Indonesia, Malaysia and Brunei. Prior to this study, its breeding biology was unknown and the population status in Indonesia was not well understood. Its breeding habitat, prey, behaviour, voice, eggs and the development of the young are described here for the first time. Breeding biology was studied in 1989 at a nest in south Sumatra, Indonesia. The nest was in the transition zone between mangrove and freshwater swamp forest. Incubation took less than 29 days, and two eggs hatched. Fish 2–7 cm long comprised 67% of the prey for feeding young. The chick was fully feathered at 52–57 days and was seen flying when 57–62 days old. The species is rare in south Sumatra. It occurs in low numbers and flocks of up to seven birds were observed. The density is estimated at 20–40 birds within 110,000 ha of primary swamp forest. At this density, the population would be below 100 birds in south Sumatra and between 100 and 300 in Indonesia. The species is threatened by development and conversion of primary swamp forest.     

BREEDING BIOLOGY OF THE GREY-FACED PETREL PTERODROMA MACROPTERA GOVLDI

The Grey-faced Petrel is a non-migratory winter breeder whose reproductive season occupies 9–10 months. Males spend more time in the burrows than females during the courtship period. Some females keep company with strange males, and may be fertilized by them, but subsequently share incubation with their mate of the previous year. The duration of the pre-laying absence of females is about two months, and of the pre-incubation absence of males about seven weeks. Since copulation is presumed to occur before this absence, these petrels seem to have evolved prolonged viability of the spermatozoa, though ovulation may take place some time before laying. Eggs are laid in late June or July but chicks are rarely reared from eggs laid after 14 July; effective laying thus lasts three weeks. The single egg is about 15·5% of the female's weight; she may be able to exert slight control over timing of oviposition. She may be required to incubate, if capable, for up to 14 days from laying but the male takes over, on average, after four days. There are three main incubation spells of 17 days' average duration, two by the male. These are of a duration such that there is usually a change-over near hatching. Incubation lasts about 55 days. There is competition for burrows, resulting in two-egg nests. Norway Rats take unattended eggs and young chicks and scavenge, but their predation (less than 10–35% of chicks per year) is not considered to be endangering the population. After initially more frequent feeds, chicks are fed approximately once a week by each parent. They do not become much heavier than adults and the growth rate is slow: about 120 days to departure. The ability to begin breeding in winter, atypical of petrels in this region, may be facilitated by three factors: improved availability of food resulting from longer nocturnal feeding time and reduced inter-specific competition; the ability to lay fertile eggs two months or more after copulation; and the brevity of the non-breeding season due to the relative proximity of a sufficient food supply.     

Long-term egg retention and parasitization in Trichogramma principum (Hym., Trichogrammatidae)

Laboratory experiments with Trichogramma principium Sug. et Sor. females that were offered Sitotroga cerealella Oliv. eggs demonstrated that less than half of the ovipositing females started oviposition during the first 2 days of the experiment, whereas the rest of the ovipositing females showed a delay in parasitization ranging from 2 to 10 days after contact with the host. Almost 10% of the wasps refused to parasitize the grain moth eggs over 12 days. The delay in parasitization may be as long as 6–8 days without any significant decrease in the number of mature ovarial eggs, in the number of eggs laid during the first 48 h of oviposition, and in the total lifetime fecundity. This egg retention is responsible for the fact that in spite of a relatively short mean duration of the oviposition period in each individual female (approximately 4 days), host parasitization by a group of simultaneously emerged wasps was almost uniformly distributed over 8–10 days. When induced, the parasitization state (i.e. the tendency to parasitize sequentially offered portions of host eggs) was stable both in the presence of a host and under host deprivation extended up to 8 days. These data provide further evidence for our hypotheses that the stability of the parasitization state in Trichogramma is based on endocrine mechanisms.     

Aufzucht von Chilemeerespelikane (Pelecanus occidentalis thagus) im Vogelpark Walsrode mit Vergleichen zu anderen publizierten Erfahrungen mit Pelikanen

The probable world first captive breeding success in Chilean Brown Pelican (Pelecanus occidentalis thagus) in captivity is reported. Two chicks were hand reared at Walsrode Birdpark, Germany in 2006. Parents were imported in October 2005 and were wild birds that had been injured and subsequently rescued. All 10 adult birds demonstrated detrimental and chronically handicaps. First eggs were laid in January 2006. Eggs were incubated artificially at 37.1 °C and 56% rel. humididty. Two chicks hatched after 33 days of incubation. First feeding was made one day after hatching in the morning. Food was given 5 times a day. Until the 8th day after hatching, exclusively cut naked baby rats were fed. For stimulating the digestion and providing a good intestinal flora Lactobacillus powder was used and food was warmed up before application. After 8 days the diet was changed to fish. For development see figures. Worth to mention is the black-purple colour of the freshly hatched chicks which became successively paler with age. Also the development of the feather areas is characteristic for this (sub)-species. Taxonomy is discussed with some morphological arguments that are typical for subspecies. Nevertheless, some indications of possible breeding barriers between subspecies could support the suggestions for species status. Hatching and rearing data are compared with dates from other zoos and species of pelicans. The good development of the Walsrode birds based on the data and methods described leaves this article useful as a reference guideline for hand rearing pelicans.     

Aufzucht von Chilemeerespelikane (Pelecanus occidentalis thagus) im Vogelpark Walsrode mit Vergleichen zu anderen publizierten Erfahrungen mit Pelikanen

The probable world first captive breeding success in Chilean Brown Pelican (Pelecanus occidentalis thagus) in captivity is reported. Two chicks were hand reared at Walsrode Birdpark, Germany in 2006. Parents were imported in October 2005 and were wild birds that had been injured and subsequently rescued. All 10 adult birds demonstrated detrimental and chronically handicaps. First eggs were laid in January 2006. Eggs were incubated artificially at 37.1 °C and 56% rel. humididty. Two chicks hatched after 33 days of incubation. First feeding was made one day after hatching in the morning. Food was given 5 times a day. Until the 8th day after hatching, exclusively cut naked baby rats were fed. For stimulating the digestion and providing a good intestinal flora Lactobacillus powder was used and food was warmed up before application. After 8 days the diet was changed to fish. For development see figures. Worth to mention is the black-purple colour of the freshly hatched chicks which became successively paler with age. Also the development of the feather areas is characteristic for this (sub)-species. Taxonomy is discussed with some morphological arguments that are typical for subspecies. Nevertheless, some indications of possible breeding barriers between subspecies could support the suggestions for species status. Hatching and rearing data are compared with dates from other zoos and species of pelicans. The good development of the Walsrode birds based on the data and methods described leaves this article useful as a reference guideline for hand rearing pelicans.     

ASPECTS OF THE BREEDING BIOLOGY OF THE FIERYNECKED NIGHTJAR

Jackson H. D. 1985. Aspects of the breeding biology of the Fierynecked Nightjar. Ostrich 56: 263–276.

A marked population of nightjars in Zimbabwe was studied intensively for four breeding seasons. This paper covers certain aspects of the breeding biology of the Fierynecked Nightjar Caprimulgus pectoralis. The male shows strong site fidelity during the breeding season (September to December), singing, feeding and breeding within an area of about 5,8 ha. There is some evidence of site defence by the male. The female shows strong mate fidelity, resulting in a pair bond for life. Egg laying starts with full moon in September and is further stimulated by the next two full moon periods. The eggs are laid directly on dense leaf litter at a site overhung by foliage. The normal clutch is two eggs (12S % are one egg) laid on successive days during the afternoon. Incubation starts with the first egg and is by the male at night and the female by day. The incubation period is 18 days. The birds respond to undue disturbance by deserting the eggs and laying a replacement clutch. The chicks usually hatch on successive afternoons; they are mobile on the first day and will move to a parent if called. Both parents feed and brood the young during twilight and moonlight; the male broods them on dark nights and the female does so by day. The species is double-brooded when time permits, the female laying again once the first brood has reached independence; she may even lay a third clutch if the second one comes to grief. There is no evidence of adults transporting eggs or young.