Parent-offspring Conflict during the Post-fledging Period in the Egyptian Vulture Neophron percnopterus (Aves,Accipitridae)

Egyptian vultures were studied during their post-fledging dependence period in northern Spain in order to detect if there were parent-offspring and sibling tensions during the transition of young to independence. The frequency of parental feedings and the frequency of movements of the parents towards their young decreased during the post-fledging period, especially in its final part. At the same time, the frequency of movements and of aggression by the young towards their parents increased. Aggression by adults to their young was not observed. Siblings disputed feedings, but there was no other evidence for sibling conflict. The results suggest that parent-offspring and sibling conflict exists and that its development is broken by the departure of young on migration. Some behavioural traits of adults (maintenance of distance from young and of intensity of nest-defence, tolerance of young during foraging trips through the home range) do not accord with parent-offspring conflict perhaps because they are related to factors other than family tension.     

Development of chicks and predispersal behaviour of young in the Eagle Owl Bubo bubo

Little quantitative information on the development and behaviour of chicks and young is available for many species, despite the crucial importance of such data and the sensitivity of this stage in a bird's life. For Eagle Owls Bubo bubo , despite the large amount of scientific literature on this species, much basic information is lacking. This study provides a photographic and morphometric guide for age estimation of nestlings and fledglings, as well as data on the call behaviour of young, and patterns of movements during the post-fledging dependence period. The most remarkable event in chick development is the rapid increase in mass, and size gain, during the first 30 and 40–45 days, respectively. Because after this time morphometric differences become less evident, young-feather development is more useful for ageing. Patterns of chick call behaviour showed that the time spent calling increased with age and, from 110 days of age, chick vocalizations were usually uniformly distributed through the whole night and most synchronized at sunset and sunrise (the maximum recorded number of vocalizations per chick and per night was 1106 calls). During the post-fledging dependence period, radiotagged Owls moved widely, up to 1500 m from the nest after the age of 80–90 days. During such movements, the mean distance among siblings increased with age, from 168 m on average for juveniles less than 100 days old, to 489 m for those older than 100 days. Definitive dispersal started when young were about 150–160 days old. Information on chick call behaviour and movements is crucial for unbiased census and nest checking, as well as for the definition of young post-fledging areas. Knowledge of the latter is very important in terms of conservation and management (especially for those species that move largely around their nest before dispersal) owing to the high mortality that can occur during this period.     

The effect of parent sex on prey deliveries to fledgling Eurasian Sparrowhawks Accipiter nisus

The relative contribution of each parent when providing for the fledglings has been recorded in only a few raptor species. We studied prey deliveries by Eurasian Sparrowhawk Accipiter nisus parents to fledglings at seven nests in southern Norway. Parents and young were fitted with radio-transmitters. Males delivered a larger number of prey to the young than did females throughout the post-fledging period (on average c.  80% of the deliveries). Two females were never observed to deliver food to the offspring, and their mates apparently raised the young to independence alone. The duration of the post-fledging period was positively related to per-capita delivery rate in the late stage.     

OBSERVATIONS ON THE POST-FLEDGING DEPENDENCE PERIOD OF CAPE VULTURES

Robertson, A. S. 1985. Observations on the post-fledging dependence period of Cape Vultures. Ostrich 56: 58–66.

Cape Vultures were observed during their post-fledging dependence period at a colony in the Cape Province, South Africa. Information is presented on the length of the period, behaviour of juveniles and of parents at the nest, survival of juveniles, aggressive interactions between parents and juveniles and retention of the nest site following breeding. At the colony, juveniles initiate contact with their parents, which supply food to their own offspring at the natal site only. Parental aggression was observed over an average period of five months after juveniles had left the nest (range 32–218 days); at two nest sites, the period overlapped with the next season's incubation period, although no transfer of food was observed during this period-of overlap.     

Factors Affecting Vocalization in Tengmalm’s Owl (Aegolius funereus) Fledglings during Post-Fledging Dependence Period: Scramble Competition or Honest Signalling of Need?

Begging behaviour of nestlings has been intensively studied for several decades as a key component of parent-offspring conflict. There are essentially two main theories to account for intensity of food solicitation among offspring: that intensity of begging is related to some form of scramble competition between nest mates or that it offers honest signalling of need to parents. The vast majority of studies which have addressed begging behaviour have been based on observations of, and experiments on, nestlings and have not considered begging behaviour, during the post-fledging period. Begging vocalizations in this post-fledging phase of dependence have rarely been studied, despite the importance of vocalizations as a communication method between offspring and parents, particularly for nocturnal species. We radiotracked 39 fledglings of the Tengmalm’s owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29 fledglings) and 2011 (n = 10 fledglings) and made 1320 nightly localizations in which we recorded presence or absence of begging calls. Within years, the most important measures related to the probability of vocalization were body condition at fledging, time of night, number of surviving siblings, age and weather conditions. Begging intensity increased with age in both years; however, in the year with low prey availability fledglings vocalized significantly more often. The main factor causing these differences between years was probably the different availability of prey, affecting breeding success, post-fledging behaviour, and thus also both short- and long-term needs of offspring. We believe that our results suggest honest signalling of their fledgling’s need.     

OBSERVATIONS ON SOME KENYA EAGLES

This paper describes the continuation of work on eagles in Embu district, Kenya, especially at Eagle Hill, which has now been under observation continuously since 1949. Observations in other parts of Kenya have been included. The ecological changes possibly affecting eagles on Eagle Hill are discussed. The population fell from a pair each of Circaetus cinereus, Aquila verreauxi, Hieraetus fasciatus spilogaster, H. dubius, Polemaetus bellicosus and Stephanoaetus coronatus in 1952 to a pair each of H. dubius, P. bellicosus and S. coronatus in 1965. Possible causes of the decline are discussed. The species of eagles are not normally aggressive to one another, in contrast to other resident species such as Falco peregrinus and Buteo rufofuscus. Although the eagles appear to be ecologically separated by food preferences and habitat this is apparently not the whole explanation for the unusual concentration of eagles on this hill. Additional breeding data are given for H.f. spilogaster, H. dubius, P. bellicosus and S. coronatus. These species rear respectively 0.56, 0.65, 0.42 and 0.44 young per pair per annum. S. coronatus breeds in alternate years and cannot breed every year because of a protracted post-fledging period in which the young is fed for up to 350 days. P. bellicosus, with about the same annual reproductive rate, does not have the same breeding rhythm. Data on reproductive rates combined with other data suggest possible life spans in the wild state of adults of H.f. spilogaster 10–11 years, H. dubius nine years, P. bellicosus 14 years, and S. coronatus 16 years. At nests of H. dubius and S. coronatus changes of mates have been recorded for 16 and 17 years respectively. In S. coronatus a change occurs about every six years and in H. dubius about every four years, indicating that S. coronatus may live about 1.5 times as long as H. dubius in the wild state. One female S. coronatus was known to live for 8.5 years as an adult. Other incomplete life spans are eight and eight years for two male S. coronatus, and eight for one female of this species. Two male H. dubius have each lived for at least eight years but no female of this species has lived for more than five years. Two proven cases of re-laying after a natural disaster are recorded, one each in H. dubius and S. coronatus. Other instances are suspected in H. dubius. The habit may be commoner than is supposed in large eagles. The history of four pairs of S. coronatus, each observed for four years or more, totalling 34 pair/ years is given. S. coronatus breeds regularly every second year unless some unusual occurrence, such as a change of mates or a failure during incubation, upsets the rhythm. S. coronatus females lay 1–2 eggs at dates varying from June–October in Kenya; breeding is not confined to the dry season. Laying dates of individual females may vary by two months between one year and another. Incubation takes 48–49 days, fledging 105–116 days. The elder of two young hatched invariably kills the younger so that no more than one young is reared. Female adults are dangerously aggressive, especially during days 30–60 of the fledging period. In 86% of cases where eggs are laid a young bird is reared. Since clutches of two in practice do not result in more than one young this represents a breeding success of 86% of the potential, a very high percentage. The sex ratio of young leaving the nest is about equal, seven males to five females, in known cases. The post-fledging period in S. coronatus is 330–350 days, and the total breeding cycle about 560 days, making it impossible for the eagles to breed every year, if they rear a young bird to independence. In the post-fledging period the young S. coronatus remains within half a mile of the nest, where it is fed by the parents, the female bringing most of the prey. The adults call to attract the young bird, which flies into the nest receiving the prey there, or rarely on a tree nearby. If the adult obtains no response from the young it may carry the prey away. Although regularly fed by its parents the young eagle kills some of its own food from at least day 61 of the period onwards, but most often in the last third of the period, being then apparently stimulated by unusual periods of privation. Almost 100% of young eagles that leave the nest are reared to independence at about 15 months old. The possible biological advantages of this protracted adolescence in survival and economy of prey are discussed. The main prey of S. coronatus is antelopes, followed by hyrax. Monkeys are rarely taken. Killing methods, times, and relations with prey are discussed. The eagles usually kill in early morning or evening, but also at other times. They may cache portions of large kills. Most prey is brought to the nest between hours 4–6 of daylight. The male S. coronatus feeds his incubating mate about once every 3–3 days. Once the young has hatched his killing rate rises to about one kill per 1.7 days. The killing rate falls slowly to one kill per two days later in the fledging period. At normal times the killing rate of adults is apparently controlled by their own appetites, and the increased killing rate of the male after hatching is an exception to this rule. During the post-fledging period the feeding rate varies from 1: 2.0 days to 1: 6.2 days, averaging 1: 3 days in 130 cases. Periods of privation may last from 5–13 days. Alternatively several kills may be brought in a day, possibly from cached portions of large kills in some cases. Long foodless periods may stimulate the young eagle to kill for itself, especially in the last third of the post-fledging period. Final independence of the young is not brought about by aggressive parental behaviour, but is probably due to increasing indifference of the young to food-bringing adults. This indifference may act as a release to the adults, breaking the rhythm of bringing food to the young, and so stimulate the onset of a new breeding cycle.     

Behaviour in the post-nestling dependence period of radio-tagged Common Buzzards Buteo buteo

Behaviour of 26 young Common Buzzards Buteo buteo was studied by systematic radiotracking during July and August 1991. After hatching between 11 May and 18 June, the young buzzards fledged when they were 43–54 days old. Distances travelled from the nest increased abruptly after birds were 65 days old, when their flight feathers had completed growth: buzzards were located more than 500 m from the nest in only 2% of records within 65 days of hatching but in 26% of records when they were older. Before their 65th day, there was an increase with age in distance from the nest, time spent flying and time spent calling, especially for buzzards with continuous woodland around the nest. The increases in distance and areas covered were greatest for broods where parents were most often present, which was at nests with the most grass and arable farmland nearby. Between their 65th and 100th days, buzzards showed no increase in activity with age and called less, especially where there was extensive woodland, and travelled farthest from nests with least neighbouring grassland; broods with few young most often had parents nearby. Young buzzards associated strongly with each other between leaving the nest and completing feather growth, but some broods later became much less cohesive. Variation in activity was not linked to sex or to the presence of 30 g back-pack radio-tags compared with 12-g leg-mounted radio-tags.     

Factors influencing family rupture and parent-offspring conflict in the Black Kite Milvus migrans

Juvenile and adult behaviour was studied at eight nests of Black Kites Milvus migrans within the Doñana Biological Reserve, Spain. Parental investment in vigilance and defence of offspring progressively decreased during the post-fledging dependence period. The number of feeds was also slightly reduced towards the end of the period. However, this does not seem to be the main factor which leads to juvenile independence. The fact that the family rupture is sudden and that the post-fledging dependence period tends to shorten as the season progresses suggests that juvenile and adult migratory urgency may be as important a factor as reduced parental investment in breaking the family ties.     

Behaviour of the female beaugregory damselfish (Stegastes leucostictus)

Much less is known about the behaviour of female beaugregory damselfish than about males of the species. This study was initiated to determine behavioural patterns and interactions of female beaugregories on the back reef of Discovery Bay Marine Laboratory, North shore of Jamaica. Females fed, patrolled, and chased intruders in a significantly larger area and ate significantly more per 15-min observation period than did males. Males spent significantly more time patrolling their territories and chased significantly more total intruders than did females. However, this difference in total chases comes from the fact that males chased the bluehead wrasse, an egg predator, significantly more often than did females while all other species of intruder were chased the same by both sexes. The distance that females travelled from their homesite to court was significantly positively correlated to female body length. This increased distance travelled may relate to mate assessment. Female beaugregory damselfish may be able to be more selective in their choice of mate with increased size and distance travelled.     

Delayed juvenile behavioral development and prolonged dependence are adaptations to desert life in the grey falcon

Rapid learning in the young of most endothermic animals can be expected to be favored by natural selection because early independence reduces the period of vulnerability. Cases of comparatively slow juvenile development continue, therefore, to attract scientific attention. In most species of birds, including raptors, the young depend on their parents for some time after fledging for the provisioning of food and for protection while they learn to become nutritionally and otherwise independent. Among raptors, post-fledging dependence periods that exceed 6 months are exclusive to the largest species and these have reproductive cycles that exceed 12 months. By contrast, young of the medium-sized grey falcon Falco hypoleucos have been reported in close company with their parents up to 12 months after fledging, that is, at a time when the adults are expected to breed again. We investigated the occurrence and characteristics of prolonged adult–juvenile association relative to other falcons and similar-sized raptors. We found that the behavioral development of grey falcon young is extremely delayed, and that they even depend nutritionally on their parents for up to 12 months after fledging. We suggest that these 2 distinctive features are, ultimately, adaptations of the grey falcon to its extreme environment, Australia’s arid and semi-arid zone, one of the hottest environments in the world.     

The function of aggressive chases by breeding Black and Red Kites Milvus migrans and M. milvus during the post-fledging dependence period

Black and Red Kites Milvus migrans and M. milvus chase other raptors approaching their nests. The study of this behaviour during the post-fledging period suggested that it reflects mainly, but not only, anti-predator behaviour. The frequency of vigilance and aggressive chases decreased through the post-fledging period as predicted by theoretical models of nest defence. Although predation risks were similar, Black Kites invested more time chasing intruders than did Red Kites. Black Kites, unlike Red Kites, chased away intruding juveniles, which may be interpreted as a behaviour to avoid investment in unrelated fledglings. Black Kites usually nest in loose colonies where the risk of, and selection pressures against, accidental investment in unrelated fledglings is likely to be greater than for Red Kites. Differences in aggressive chases by Black and Red Kites are better related to this than to different predation risks.     

Post-fledging interactions between the Common Cuckoo Cuculus canorus and its cavity-nesting Common Redstart Phoenicurus phoenicurus host

Brood parasite–host interactions during the incubation and nestling stages have been well studied, but the post-fledging period remains virtually unknown. Using radiotracking, we provide the first detailed data on post-fledging interactions between the Common Cuckoo Cuculus canorus and its only regular cavity-nesting host, the Common Redstart Phoenicurus phoenicurus. Cuckoos raised alone (‘solitary’) fledged at higher mass, with higher wing and tarsus length and started to fly at a younger age than Cuckoos raised alongside young Redstarts (‘mixed’). However, a further 23 fledging and post-fledging parameters measured at five pre-determined times (fledging, first-flight, predation, starvation, independence) did not differ between solitary and mixed Cuckoos. In addition, none of the parameters measured during the post-fledging period (growth, dispersal distances, number of flights) differed between solitary and mixed Cuckoos. Redstart fledglings from non-parasitized broods (‘solitary’) showed generally similar fledging and post-fledging parameters to fledglings reared alongside a Cuckoo (‘mixed’). Surprisingly, there were no significant differences in post-fledging predation rate, starvation or overall survival rates between mixed and solitary Cuckoos or mixed and solitary Redstarts. Thus, during the post-fledging period, mixed Cuckoo fledglings successfully compensated for the poorer performance experienced during the nestling stage whereas mixed and solitary Redstarts did not differ in any measured parameters. This suggests that the regular occurrence of mixed broods in this host–parasite system – which is unique among the many Cuckoo hosts – is evolutionarily stable for both hosts and parasites.     

Differential Movement Patterns of Juvenile Tengmalms Owls (Aegolius funereus) during the Post-Fledging Dependence Period in Two Years with Contrasting Prey Abundance

Fledgling behaviour and movement patterns throughout the post-fledging dependence period (PFDP), especially in relation to changing environmental conditions, have been rarely studied, despite the fact that this period is recognized as of crucial significance in terms of high mortality of juveniles. The PFDP can extend over quite a protracted period, particularly in birds of prey, and a knowledge of the movement patterns of individuals is fundamental for understanding mechanisms underlying survival, habitat use and dispersion. We radiotracked 39 fledglings of the Tengmalm’s owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29) and 2011 (n = 10) and obtained 1455 daily locations. Fledglings reached independence on average in 45 days after fledging in 2010 (n = 22) and 57 days in 2011 (n = 6). Within years, the most important measures influencing the distance moved from the nest box were age of fledglings and number of surviving siblings present. Individual home range size and duration of PFDP in particular were dependent on maximal number of siblings seen outside the nest box. In the season with low prey availability fledglings were observed at greater distances from the nest box than in the year with higher prey availability (mean distance: 350 m in 2010 and 650 m in 2011) and occupied larger home ranges (mean: 30.3 ha in 2010 and 57.7 ha in 2011). The main factor causing these differences between years was probably the different availability of prey in these two years, affecting breeding success and post-fledging survivorship of the Tengmalm’s owls.     

Intraspecific brood-parasitism and dispersal in fledgling Sparrowhawks Accipiter nisus

The progeny of early-nesting Sparrowhawks Accipiter nisus have a higher survival rate than those of late nesters. To ascertain the reasons for greater survival in early-season Sparrowhawk fledglings, I studied post-fledging dispersal behaviour in this species by direct observations and radio-tracking during 3 years in Rockingham Forest, Northamptonshire, U.K.
Post-fledging brood-parasitism was found among early-dispersed young of both sexes.
Early-dispersed young spent up to 6 days being fed by the parents of other fledged, but still dependent, broods, as far as 6 km from their own nests.
Three broods were provided with supplementary food for 4 weeks, starting 1 week before expected dispersal. These young dispersed when significantly older than young from control broods. In both groups, males dispersed, on average, 3–4 days earlier than females. The ultimate dispersal age of young in control broods was negatively correlated with their rate of mass gain during the nestling period. Unlike the young of the control broods, fledglings in broods with augmented food were usually silent.
These findings offer an explanation for why Sparrowhawk young that disperse early in the season survive better than those which disperse late.     

Habitat exploration and use in dispersing juvenile flying squirrels

1. Variation in behaviours involved in habitat selection is important for several evolutionary and ecological processes. For example, habitat use during dispersal may differ from breeding habitat use, and for dispersers the scale of habitat familiarity is determined by exploratory behaviour. We studied habitat use and exploration of 56 radio-collared juvenile flying squirrels Pteromys volans L. within natal home range and during dispersal, and compared habitat use between juveniles and 37 adults within breeding home range. 2. Before dispersal, young flying squirrels actively moved around the natal site. Surprisingly, long-distance dispersers explored less than short-distance dispersers, but philopatric individuals explored similar distances as dispersers. Females explored less than males, although females are the more dispersive sex in flying squirrels. 3. For most of the individuals the settlement area was unfamiliar due to long dispersal distance. Consequently, direction and distance of exploration were not very strong predictors of settlement location. However, individuals familiar with the settlement area concentrated exploration to that area. Exploration did not correlate with short-term survival. 4. Dispersers preferred breeding habitat while dispersing, but were found more often in matrix habitat than juveniles within natal, or adults within breeding, home ranges. 5. We conclude that familiarity does not determine settlement as much as, for example, availability of the habitat for flying squirrels. Based on our results, it also seems clear that data on adult habitat use are not enough to predict habitat use of dispersing individuals. In addition, our results support the recent view that short- and long-distance dispersers may need to be analysed separately in ecological and evolutionary analyses.     

The ontogeny of the homing pigeon navigational map: evidence for a sensitive learning period

Homing pigeons can learn a navigational map by relying on the heterogeneous distribution of atmospheric odours in the environment. To test whether there might be a sensitive period for learning an olfactory-based navigational map, we maintained a group of young pigeons in an aviary screened from the winds until the age of three to four months post-fledging. Subsequently, the screens were removed and the pigeons were exposed to the winds and the environmental odours they carry for three months. One control group of pigeons was held in a similar aviary but exposed to the winds immediately upon Hedging, while another control group of pigeons was allowed free-flight. When the pigeons from the three groups were released from two distant release sites at about six months of age post-fledging, the two control groups were found to be equally good at orientating and returning home, while the experimental pigeons held in the shielded aviary for the first three months post-fledging were unable to orientate homeward and they were generally unsuccessful in returning home. This result supports the hypothesis that environmental experience during the first three months post-fledging is critical for some aspect of navigational map learning and that navigational map learning displays sensitive period-like properties.     

Do fledgling and pre‐breeding Common Swifts Apus apus take part in aerial roosting? An answer from a radiotracking experiment

This study has shown that fledgling Common Swifts Apus apus spend the first post-fledging night of their life on the wing and that pre-breeders also spend the full night on the wing. Even though this work was conducted during an unusually cold, wet period, the results show that fledglings do not return to their natal colony in the week after fledging. It also demonstrates that yearlings are only slightly more likely than fledglings to spend any time at a particular colony, but are more likely to move from colony to colony. Older pre-breeders are more likely to spend more time at and revisit a particular colony more often than yearlings. It is our observation that only right at the end of the breeding duties will the parents participate in an evening ascent, and even then many of them return to their nest for the evening. Breeding adults displayed the greatest devotion to a particular colony. But even among such adults we detected some that ceased caring for their young a few days prior to their fledging. Adults roost in their nestbox if they meet with bad weather.     

Post-fledging body mass increase in Common Terns Sterna hirundo: influence of age, sex and year

We studied the inter-year and inter-sex variation of the post-fledging body mass development of Common Terns Sterna hirundo in 2000 and 2001 at the Banter See colony, northern Germany. Here, post-fledglings can be identified and weighed remotely and automatically by a transponder system that makes use of automated balances installed at the colony. Individuals were sexed with PCR amplification methods. After fledging, young generally continued to increase their mass. However, in 2000, the young did not significantly increase their mass during the post-fledging period. In 2001, conditions were more favourable and body mass increased continuously. Further, in 2001, male post-fledglings were significantly heavier than female post-fledglings. Once having left the colony area (on average 18–23 days after fledging in 2000, and 14–16 days after fledging in 2001), post-fledgling body mass had still not reached adult body mass. The longer a juvenile stayed at the colony, the higher was its final body mass, which if acting as a threshold level may control departure time. Neither brood size nor hatching order affected post-fledging mass or period. In the unfavourable year 2000, when many individuals were found dead after fledging, fledging age but not fledging mass was found to be a predictor of post-fledging survival before departure: individuals fledging when older had a lower survival probability. Our results stress the importance of the post-fledging period for body mass increase and survival prior to departure. The variation in post-fledging mass growth between years and between the sexes is discussed with respect to parental effort and a possible selective provisioning of sons over daughters.     

Parent-offspring conflict over duration of parental care and its consequences in tawny owls Strix aluco

In species defending territories, fitness of newly independent juveniles could depend on phenotypic quality or early access to vacant resources as a result of rapid dispersal. In the first case, parent-offspring conflict will arise when parents cease feeding maturing offspring while these still demand provisioning. In the latter case, the young should decide when to stop begging to search for vacant territories. I radio-tracked 72 juvenile tawny owls from independence to sexual maturity to investigate whether parents or offspring decided the timing of the onset of independence and compare effects of age versus date of independence on survival and reproductive status. Juvenile owls stopped begging when 90–123 d old. This was synchronous within broods, independent of gender or age rank. Independence age of cross-fostered young varied across foster nests but was independent of hatching nest. After independence, young roosted in their parents' territory for 18 d on average before dispersal. This suggests that juvenile owls would rather extend dependency than disperse early. As predicted from this behaviour, age of independence had a positive influence on survival and reproductive status at maturity, whereas there were no effects of date of independence.     

Behaviour of the yellow-eyed penguin chick

The ontogeny of yellow-eyed penguin ( Megadyptes antipodes ) chick behaviour follows the order of development determined by Nice (1962) for several species of birds, and by Spurr (1975) for the Adélie penguin ( Pygoscelis adeliae ). Feeding and comfort behaviours are the first to develop, followed by locomotion and aggressive behaviour.
Active solicitation of food may occur at one day of age. Chicks initially use non-visual cues to mediate begging. After their eyes open on the third or fourth day there is an increase in the use of visual stimuli, and begging occurs most often following adult nest relief. Sibling rivalry is not intense, occurring least during feeding, and in general both chicks are fed at each session.
The chicks are brooded for the first 21–25 days. At sparsely vegetated nest sites overheating may occur after 21 days and down-covered chicks will seek shade and pant in hot weather.
Throughout the 6–7 weeks of the guard phase there is a decrease in the amount of time spent resting in a prone posture, and an increase in exploratory, locomotory behaviour. During the post-guard phase, and until fledging and independence at 15 weeks after hatching, chicks may wander up to 20 m from the nest bowl during exploration, shade-seeking and feeding.
Adults feed only their own chicks, and chicks appear to beg only from their parents. Dense vegetation and long distances between nests tend to restrict contact between adults and chicks from neighbouring nests, and prevent the formation of large chick crèches.