Vulture flight behavior and implications for aircraft safety

Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solar-powered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006–30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than did turkey vultures in all seasons except summer when altitudinal distributions (above ground level) did not differ. Although we recorded maximum altitudes of 1,578 m for black vultures and 1,378 for turkey vultures, most flights were low altitude. A matrix of vulture flight altitude versus time of day revealed that >60% of vulture flight activity occurred from 4 hr to 9 hr after sunrise at altitudes below 200 m. Continuation of aggressive harassment coupled with flexible training schedules to avoid times and altitudes of high vulture activity will decrease hazards to aircraft posed by these birds. © 2011 The Wildlife Society.     

Rapid population declines of Egyptian vulture (Neophron percnopterus) and red-headed vulture (Sarcogyps calvus) in India

Since the early 1990s, large and rapid population declines of three species of vulture ( Gyps spp.) endemic to south Asia have occurred on the Indian subcontinent and have led to these species being listed by IUCN as critically endangered. Evidence of rates of population decline, cause of death and toxicity is consistent with these declines being caused by poisoning of vultures through the ingestion of tissues from livestock treated with the anti-inflammatory drug diclofenac. In this paper, analysis of repeated surveys in and near protected areas widely spread across India shows that populations of two other vulture species, Egyptian vulture Neophron percnopterus and red-headed vulture Sarcogyps calvus , have also declined markedly and rapidly, but probably with a later onset than Gyps vultures in the same region. The declines continued at least up to 2003. It is recommended that these two species are considered for inclusion in the IUCN Red List and for urgent remedial conservation measures. Research is needed to determine whether or not the principal cause of these declines is diclofenac poisoning and to establish population trends in other scavenging birds in the Indian subcontinent.     

Chromosome banding and DNA replication patterns in bird karyotypes

The karyotypes of the domestic chicken (Gallus domesticus), Japanese quail (Coturnix coturnix), and griffon vulture (Gyps fulvus) were studied with a variety of banding techniques. The DNA replication patterns of bird chromosomes, analyzed by incorporation of 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT), are presented here for the first time. In particular, the time sequence of replication of the ZZ/ZW sex chromosomes throughout the S-phase was meticulously analyzed. BrdU and dT incorporation are very useful methods to identify homoeologies between karyotypes, as well as rearrangements that occurred in the macroautosomes during speciation. The Z chromosomes of the three birds displayed the same replication patterns, indicating a high degree of evolutionary conservation. In the homogametic male, BrdU and dT incorporation revealed no evidence of asynchronous replication between euchromatic bands in the ZZ pair. The same was true of the three Z chromosomes in a triploid-diploid chimeric chicken embryo. Minor replication asynchronies between the homologous ZZ or ZZZ chromosomes were restricted to heterochromatic C-bands. These results confirm that, in the ZZ male/ZW female sex-determining system of birds, dosage compensation for Z-linked genes does not occur by inactivation of one of the two Z chromosomes in the homogametic male. The heterochromatic W chromosomes of the three species showed bright labeling with distamycin A/mithramycin counterstain-enhanced fluorescence and exhibited significantly delayed DNA replication. The nucleolus organizers of birds, frequently located in microchromosomes, were also distinguished by bright distamycin A/mithramycin fluorescence.     

Testing the Goodness of Supplementary Feeding to Enhance Population Viability in an Endangered Vulture

Background

Human-predator conflicts are directly or indirectly threatening many species with extinction. Thus, biologists are urged to find simple solutions to complex situations while avoiding unforeseen conservation outcomes. The provision of supplementary food at artificial feeding sites (AFS) is frequently used in the conservation of scavenger bird populations currently suffering from indirect poisoning, although no scientific studies on its effectiveness have been conducted.

Methodology/Principal Findings

We used a long-term data set of 95 individually marked birds from the largest European core of the endangered bearded vulture (Gypaetus barbatus) to test the long-term effects of specific AFS for bearded vultures on their survival rates (by CMR models) and population dynamics (by Monte Carlo simulations) in an area where fatalities derived from illegal poisoning and the use of other toxics like veterinary drugs have increased over the last several years. Our data support the positive relationship between the use of AFS and survival. However, contrary to theoretical predictions (e.g. high and more stable adult survival among long-lived species), the use of AFS increased only survival of pre-adults. Moreover, AFS buffered the effects of illegal poisoning on this age-class, while adult survival decreased over years. Our simulations predicted a maximum value of extinction probability over a time horizon of 50 years. Population projections run with survival rates expected in scenarios without poisoning predicted the situation of least conservation concern, while including only AFS can maintain a large floater surplus that may delay population decline but fails to reduce poisoning risk among adults.

Conclusions/Significance

Although AFS are not effective to save bearded vultures from an expected population decline, they delay population extinction and can be a useful tool for prolonging population viability while combating illegal and indirect poisoning. The eradication of different sources of poisoning is of top priority to ensure the long-term viability of this and many other species.     

Development of the glycogen body of the Japanese quail, Coturnix japonica. I. Light microscopy of early development

The glycogen body is a functionally enigmatic structure located in lumbosacral region of the spinal cord in birds. This tissue is unique to birds, and, although it is believed to be present in all species, studies on the glycogen body to date have been confined largely to the domestic chicken. The present study is the first to describe the glycogen body of the Japanese quail (Coturnix japonica) during incubation and at hatching. Light microscopy and histochemistry were used to identify the glycogen body in the spinal cord of the developing quail beginning at 7 days of incubation and to ascertain the presence of nerve fibers in that tissue at hatching.     

Experimental lead poisoning in turkey vultures (Cathartes aura)

Lead-induced mortality appears to have been a major factor in the decline of the California condor (Gymnogyps californianus). We orally dosed turkey vultures (Cathartes aura) with BB-sized lead shot from January 1988 through July 1988 to determine physiologic response (delta-aminolevulinic acid dehydratase inhibition, erythrocyte protoporphyrin levels, anemia), diagnostic tissue lead concentrations (blood, liver, and kidney), and comparative sensitivity of this species. Two turkey vultures died and two became so intoxicated they were euthanized. Overall, responses of measured parameters were comparable to other species exposed to lead although there was considerable individual variation. Survival time (143-211 days), even with the large numbers of shot and constant redosing, was much longer than reported for other species of birds, suggesting considerable tolerance by turkey vultures to the deleterious effects of lead ingestion. Based on these observations, turkey vultures appear to be poor models for assessing the risk of lead poisoning to California condors or predicting their physiologic response.     

Toxicity of non-steroidal anti-inflammatory drugs to Gyps vultures: a new threat from ketoprofen

Three Gyps vulture species are on the brink of extinction in South Asia owing to the veterinary non-steroidal anti-inflammatory drug (NSAID) diclofenac. Carcasses of domesticated ungulates are the main food source for Asia''s vultures and birds die from kidney failure after consuming diclofenac-contaminated tissues. Here, we report on the safety testing of the NSAID ketoprofen, which was not reported to cause mortality in clinical treatment of scavenging birds and is rapidly eliminated from livestock tissues. Safety testing was undertaken using captive non-releasable Cape griffon vultures (Gyps coprotheres) and wild-caught African white-backed vultures (G. africanus), both previously identified as susceptible to diclofenac and suitable surrogates. Ketoprofen doses ranged from 0.5 to 5 mg kg⁻¹ vulture body weight, based upon recommended veterinary guidelines and maximum levels of exposure for wild vultures (estimated as 1.54 mg kg⁻¹). Doses were administered by oral gavage or through feeding tissues from cattle dosed with ketoprofen at 6 mg kg⁻¹ cattle body weight, before slaughter. Mortalities occurred at dose levels of 1.5 and 5 mg kg⁻¹ vulture body weight (within the range recommended for clinical treatment) with the same clinical signs as observed for diclofenac. Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies. Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in other regions of the world where vultures access livestock carcasses. The only alternative to diclofenac that should be promoted as safe for vultures is the NSAID meloxicam.     

INVERSE RELATIONSHIP BETWEEN FUNCTIONAL MATURITY AND EXPONENTIAL GROWTH RATE OF AVIAN SKELETAL MUSCLE: A CONSTRAINT ON EVOLUTIONARY RESPONSE

In this study, we investigate whether a tissue-level constraint can explain the general inverse relationship between growth rate and precocity of development in birds. On the whole, altricial (dependent) chicks grow three to four times faster than the less dependent, more able chicks of precocial species of similar adult mass. We suggest that an antagonism between growth and acquisition of mature function in skeletal muscle constrains postnatal growth and development in most species of birds. Altricial species, represented by European starlings in this study, hatch with skeletal muscle having low capacity for generating force but grow rapidly. Conversely, precocial species (northern bobwhite quail and Japanese quail), hatch with relatively mature skeletal muscle, especially in their legs, but grow more slowly. As development proceeds in all species, exponential growth rates decrease as muscles acquire adult levels of function. Among four variables associated with muscle function, exponential growth rate (EGR) was negatively correlated with pyruvate kinase activity (glycolysis), potassium concentration (electrical potential), and dry weight fraction (contractile proteins) in both pectoral and leg muscles but not with citrate synthase activity (aerobic metabolism) in either set of muscles. For pectoral muscle, these variables accounted for 87% of the total variation in EGR in all three species combined despite a twofold difference in growth rates between the starling and quail. EGRs of leg muscle (51% of variation accounted for) were less than predicted by the pectoral-muscle equation in quail during the early part of the postnatal period and in starlings during the late postnatal period. This result would not contradict a growth rate/maturity constraint hypothesis if EGRs were down-regulated for allometric or other considerations.     

Ontogeny of the rhythmic melatonin production in a precocial and an altricial bird,the Japanese quail and the European starling

A distinct daily rhythm of melatonin production was found in the pineal gland of both precocial Japanese quail (Coturnix coturnix japonica) and altricial European starling (Sturnus vulgaris) during the first day of postembryonic life. Rhythmic melatonin production was reflected in a rhythmic profile in the general circulation. Significant day-night differences in melatonin content were also observed in the eyes of Japanese quail.The amplitude of the rhythm in the quail pineal gland increased steadily during the first two weeks of postem-bryonic life. A transient increase in maximum melatonin concentration was observed at the end of the first week of life in the plasma but not in the pineal gland of quail suggesting that a metabolizing pathway or a changed ocular contribution may influence the melatonin profile in the circulation and its availability to other tissues. There was no delay in the postembryonic development of melatonin rhythmicity in the altricial starling in comparison with the precocial quail. The amplitude of the plasma melatonin rhythm did not increase over the first week of life in starlings as it did in quail and the only significant increase was found between 6- and 17-day old starlings.In general, the development of the rhythm resulted from an increase of dark-time values. The day-time concentrations were low in all age groups of both species. A one-hour light pulse suppressed the high dark-time melatonin concentrations in 1-, 7- and 14-day old Japanese quail as well as in 7- and 14-day old European starlings. The manner in which the rhythm develops suggests that the circadian pacemaker(s) as well as the mechanisms of photoreception and entrainment are developed in hatchlings of both species in spite of their otherwise different developmental strategies.     

Identification of the suprachiasmatic nucleus in birds

Circadian rhythms are generated by an internal biological clock. The suprachiasmatic nucleus (SCN) in the hypothalamus is known to be the dominant biological clock regulating circadian rhythms in mammals. In birds, two nuclei, the so-called medial SCN (mSCN) and the visual SCN (vSCN), have both been proposed to be the avian SCN. However, it remains an unsettled question which nuclei are homologous to the mammalian SCN. We have identified circadian clock genes in Japanese quail and demonstrated that these genes are expressed in known circadian oscillators, the pineal and the retina. Here, we report that these clock genes are expressed in the mSCN but not in the vSCN in Japanese quail, Java sparrow, chicken, and pigeon. In addition, mSCN lesions eliminated or disorganized circadian rhythms of locomotor activity under constant dim light, but did not eliminate entrainment under light-dark (LD) cycles in pigeon. However, the lesioned birds became completely arrhythmic even under LD after the pineal and the eye were removed. These results indicate that the mSCN is a circadian oscillator in birds.     

Polymorphism of dopamine receptor D4 exon I corresponding region in chicken

In stockbreeding, there are indications that behavioral traits of livestock have an effect on breeding and production. If the variation in individual behavior is related to that in neurotransmitter-related genes such as in humans, it would be possible to breed pedigrees composed of individuals having behavioral traits that are useful to production and breeding using selection based on genotypes. In this study, we investigated the exon I region of dopamine receptor D4 (DRD4), in which variation is related to psychiatric disorder in humans, in major poultry species namely Japanese quail (Coturnix japonica), chicken (Gallus gallus), ring-necked pheasant (Phasianus colchicus) and helmeted guinea fowl (Numida meleagris). Furthermore, we investigated Japanese cormorant (Phalacrocorax capillatus) and Japanese jungle crow (Corvus macrorhynchos) as an out-group. In these species of birds, the repeat of proline was identified in the region corresponding to the human polymorphic region. The repeat number was 9 in Japanese quail, ring-necked pheasant and Japanese cormorant; 12 in helmeted guinea fowl; and 3 in Japanese jungle crow. However, no polymorphism was found in these species. In contrast, polymorphism was observed in chicken and two alleles with 8 and 9 repeats were identified. Although 9 repeats (allele 9) were predominant in most chicken breeds, Black Minorca had only 8 repeats (allele 8). Intra-breed polymorphism was found in 6 out of 12 breeds, and two alleles (alleles 8 and 9) were detected in these breeds. This polymorphism, which is the first to be reported on a neurotransmitter-related gene in birds, would contribute significant information for elucidation of differences in behavioral traits in chicken breeds.     

Comparison of migratory tendency in European Quail Coturnix c. coturnix, domestic Japanese Quail Coturnix c. japonica and their hybrids

Since the 1970s, the decline of the occidental populations of European Quail Coturnix c. coturnix , a partial migrant Galliform species, has driven the release of domestic Japanese Quail Coturnix c. japonica into the wild as game birds. Recent experiments suggest that reproductive isolating mechanisms have not developed to prevent hybridization between European and Japanese Quail. To assess the potential impact of hybridization between the subspecies in the wild, this study aims to compare the migratory characteristics of captive European Quail, domestic Japanese Quail, F₁ hybrids and a backcross. In a laboratory experiment, birds hatched in summer and reared under a natural photoperiod were transferred during winter to an artificial photoperiod (light–dark) of 14 : 10 h. Behavioural (migratory restlessness, crowing activity in males) and physiological (sexual development, fat accumulation, body mass) measures were recorded. Domestic Japanese Quail showed no migratory tendency in response to the increased day length. F₁ hybrids showed rapid sexual development and few of them exhibited the typical profile of a migrant bird. Backcrosses showed great variation in their response, comparable with those of the European Quail. Therefore, hybridization could lead to an increased proportion of quail showing sedentary rather than migratory behaviour. Furthermore, hybrids that do show migratory behaviour have the potential to facilitate Japanese gene flow into areas where the release of domestic Quail as game birds is not yet practised.     

Microsatellite loci in Japanese quail and cross-species amplification in chicken and guinea fowl

In line with the Gifu University''s initiative to map the Japanese quail genome, a total of 100 Japanese quail microsatellite markers isolated in our laboratory were evaluated in a population of 20 unrelated quails randomly sampled from a colony of wild quail origin. Ninety-eight markers were polymorphic with an average of 3.7 alleles per locus and a mean heterozygosity of 0.423. To determine the utility of these markers for comparative genome mapping in Phasianidae, cross-species amplification of all the markers was tested with chicken and guinea fowl DNA. Amplification products similar in size to the orthologous loci in quail were observed in 42 loci in chicken and 20 loci in guinea fowl. Of the cross-reactive markers, 57.1% in chicken and 55.0% in guinea fowl were polymorphic when tested in 20 birds from their respective populations. Five of 15 markers that could cross-amplify Japanese quail, chicken, and guinea fowl DNA were polymorphic in all three species. Amplification of orthologous loci was confirmed by sequencing 10 loci each from chicken and guinea fowl and comparing with them the corresponding quail sequence. The microsatellite markers reported would serve as a useful resource base for genetic mapping in quail and comparative mapping in Phasianidae.     

A Global Review of Causes of Morbidity and Mortality in Free-Living Vultures

Vulture species worldwide play a key role in ecosystems as obligate scavengers, and several populations have had precipitous declines. Research on vulture health is critical to conservation efforts including free-living vultures and captive breeding programs, but is limited to date. In this systematic review, we determined the reported causes of free-living vulture species morbidity and mortality worldwide. The most commonly reported cause of mortality was from toxins (60%), especially lead and pesticides, followed by traumatic injury (49%), including collisions with urban infrastructure and gunshot. Neglected areas of research in free-living vulture health include infectious diseases (16%), endocrine and nutritional disorders (6%), and neoplasia (<?1%). Almost half of the studies included in the review were conducted in either Spain or the USA, with a paucity of studies conducted in South America and sub-Saharan Africa. The highest number of studies was on Griffon (Gyps fulvus) (24%) and Egyptian vultures (Neophron percnopterus) (19%), while half of all vulture species had five or fewer studies. Future investigations on free-living vulture health should focus on neglected areas of research, such as infectious diseases, and areas with gaps in the current literature, such as South America, sub-Saharan Africa, and under-studied vulture species.

     

Are farm-reared quails for game restocking really common quails (Coturnix coturnix)?: a genetic approach

The common quail (Coturnix coturnix) is a popular game species for which restocking with farm-reared individuals is a common practice. In some areas, the number of released quails greatly surpasses the number of wild breeding common quail. However, common quail are difficult to raise in captivity and this casts suspicion about a possible hybrid origin of the farmed individuals from crosses with domestic Japanese quail (C. japonica). In this study we used a panel of autosomal microsatellite markers to characterize the genetic origin of quails reared for hunting purposes in game farms in Spain and of quails from an experimental game farm which was founded with hybrids that have been systematically backcrossed with wild common quails. The genotypes of these quail were compared to those of wild common quail and domestic strains of Japanese quail. Our results show that more than 85% of the game farm birds were not common quail but had domestic Japanese quail ancestry. In the experimental farm a larger proportion of individuals could not be clearly separated from pure common quails. We conclude that the majority of quail sold for restocking purposes were not common quail. Genetic monitoring of individuals raised for restocking is indispensable as the massive release of farm-reared hybrids could represent a severe threat for the long term survival of the native species.     

Lead poisoning in captive Andean condors (Vultur gryphus)

Elevated lead in the tissues of raptors, especially those that scavenge, is a common occurrence, and lead poisoning appears to be a significant problem in the ongoing recovery effort for California condors (Gymnogyps californianus). Elevated blood lead levels have been found in released birds, and a number of birds have died of lead poisoning. In earlier work, we dosed turkey vultures (Cathartes aura) with lead shot but found them to be a poor model for lead poisoning. In this study, we dosed four Andean condors (Vultur gryphus) with lead shot and found them to be quite sensitive, as two of the birds died and the other two exhibit signs of lead poisoning within 50 days. All lead-responsive parameters were affected, and regurgitation of dosed shot occurred only once. The response of the Andean condors appeared to mimic California condors, suggesting that once exposed to lead, the possibility of survival is poor. This is consistent with observations in the wild, where otherwise healthy birds exposed to metallic lead quickly succumb. At the very least, the release program has to maintain constant surveillance and an active lead monitoring program.     

Removing the threat of diclofenac to critically endangered Asian vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genusGyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captiveGyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vultureGyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered AsianGyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40G. africanus. Subsequently, sixG. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species(Gyps bengalensis,Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity toGyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India.     

Estimating updraft velocity components over large spatial scales: contrasting migration strategies of golden eagles and turkey vultures

Soaring birds migrate in massive numbers worldwide. These migrations are complex and dynamic phenomena, strongly influenced by meteorological conditions that produce thermal and orographic uplift as the birds traverse the landscape. Herein we report on how methods were developed to estimate the strength of thermal and orographic uplift using publicly available digital weather and topography datasets at continental scale. We apply these methods to contrast flight strategies of two morphologically similar but behaviourally different species: golden eagle, Aquila chrysaetos, and turkey vulture, Cathartes aura, during autumn migration across eastern North America tracked using GPS tags. We show that turkey vultures nearly exclusively used thermal lift, whereas golden eagles primarily use orographic lift during migration. It has not been shown previously that migration tracks are affected by species-specific specialisation to a particular uplift mode. The methods introduced herein to estimate uplift components and test for differences in weather use can be applied to study movement of any soaring species.     

Poison-related mortality effects in the endangered Egyptian vulture (<Emphasis Type="Italic">Neophron percnopterus</Emphasis>) population in Spain

A total of 211 poisoning incidents registered over the period 1990–2007 and affecting 294 Egyptian vultures (Neophron percnopterus) were studied to address the impact of poison-related mortality in the Spanish population. Poison-related mortality mainly affected the birds on an individual level, with low numbers of individuals being found in each incident (mean 1.39) with 94.9% being adults. Deaths were largely recorded (81.8%) during the breeding season, with mortality peaking during May and June (52.1%). In contrast with other raptor species, a high proportion of adult individuals (74.2%) were found in the nest or its surroundings. Age-related differences in the poisoning rate are probably related with different feeding and behavioral strategies between age classes. The illegal use of poison to control predators was the main cause of mortality (93.8%), and particularly in small hunting reserves (74.9%), since the kind of food resources that adults exploit are coincident with the type of baits employed to illegally control predators and the preferred habitat coincides with areas of small game hunting. Our results suggest that poisoning is probably one of the main causes of Egyptian vulture mortality in Spain. The eradication of the illegal use of poisoning and supplementary feeding in specific territories to provide safe food seems priority for its conservation.     

Bone crushing carnivores and their significance to osteodystrophy in griffon vulture chicks

The natural removal of 89 ungulate carcasses by predators and scavengers was monitored in various wildlife reserves and ranching areas of South Africa. Carnivores responsible for the bone remains were determined. Spotted hyaenas and, to a lesser extent, Brown hyaenas, were the only carnivores that regularly chewed bones. When hyaenas were absent, months of weathering were required before the smaller bones became disarticulated and able to be removed by vultures. The bone-collecting behaviour and related aspects of breeding of two species of griffon vulture were studied at five different nesting colonies in southern Africa—one Cape vulture colony and one White-backed vulture colony in or near wildlife reserves, as well as two Cape vulture colonies and one White-backed vulture colony in ranching land. A total of 2825 bones was found in or below the vulture nests. These bones were categorized and measured. Hyaena-produced bone fragments were found only in the colonies in the wild areas—none of the 387 chicks examined here had osteodystrophy (metabolic bone disease). By contrast, in the ranching areas, vultures collected larger and less fragmented bones. Many Cape vulture chicks had osteodystrophy (130 of 1917 examined), as did two White-backed vulture chicks (of 196 examined). In 1977, artificial feeding stations, 'restaurants' where carcass skeletons were crushed, were established for Cape vultures. Since then, the incidence of osteodystrophy has declined from 17% to 2–5% in 1983. It is clear that bone fragments are an essential dietary requirement, providing calcium for correct skeletal growth of griffon vulture chicks.