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Bill malformation in Scopoli's Shearwater Calonectris diomedea chicks
Abstract
We report three cases of bill malformation in Scopoli’s Shearwater Calonectris diomedea on Linosa Island (Sicily, Italy) that were found
during monitoring of the colony over a 13-year period. The cases were observed in pre-fledging chicks; two of the birds were also in poorer
body condition compared with chicks of the same age. No adults in the colony have been found with similar bill malformations despite a
much larger sample of recorded adults. We suggest that the observed malformations impair survival and that the chicks we encountered
would likely starve after fledging. The frequency of bill malformation found on Linosa is less than one percent, which is consistent with
cases reported in the literature for other species.
... Local ora is of exceptional interest and include 250 owering plants (Surico, 2020) as well as several endemic plants both on Lampedusa and Linosa Pasta and La Mantia, 2013). The island of Linosa hosts the largest European colony of the seabird Scopoli's Shearwater (Roatti et al., 2019). ...
Lampedusa is today best known in relation to migration. The island has confronted one migration crisis after the other for the past three decades, resulting in extensive media coverage. Whereas Lampedusa, a small island in the central Mediterranean region, has an economy mainly based on tourism, its name remains associated with migration, which is believed to negatively impact the island’s image and the performance of its tourism sector. On the other hand, migration has to some extent, put Lampedusa on the map, helping the island gain popularity. The island’s existing tourism model is based on sun, sand, and sea (3S) and is made attractive by its beaches, one of which has ranked as the best beach in the world, as well as by marketing efforts presenting Lampedusa as 'the Caribbean island of the Mediterranean'. However, migration and 3S are camouflaging other resources that are key to the island’s image. Lampedusa has a terrestrial nature reserve as well as a marine protected area that is home to several charismatic marine species, making it an ideal ecotourism destination. These resources can be used not only to depict a more representative image of the island but also to develop a sustainable tourism model that is suitable to a small island.
Today the Mediterranean distribution of Cory ' s Shearwaters is believed to be well known. New colonies may be dlscovered, but certainly the largest ones are known. Many data were published durlng the last ten years and we believe to have a satysfactory knowledge of their biology, though some problems, as the winter movements of each population, the first breeding age and the ratio immatures/adults are stlll to be examined carefully .
Background:
Avian keratin disorder (AKD) is an epizootic of debilitating beak deformities, first documented in black-capped chickadees (Poecile atricapillus) in Alaska during the late 1990s. Similar deformities have now been recorded in dozens of species of birds across multiple continents. Despite this, the etiology of AKD has remained elusive, making it difficult to assess the impacts of this disease on wild populations. We previously identified an association between infection with a novel picornavirus, Poecivirus, and AKD in a small cohort of black-capped chickadees.
Methods:
To test if the association between Poecivirus and AKD holds in a larger study population, we used targeted PCR followed by Sanger sequencing to screen 124 symptomatic and asymptomatic black-capped chickadees for Poecivirus infection. We further compared the efficacy of multiple non-terminal field sampling methods (buccal swabs, cloacal swabs, fecal samples, and blood samples) for Poecivirus screening. Finally, we used both in situ hybridization and a strand-specific expression assay to localize Poecivirus to beak tissue of AKD-positive individuals and to determine if virus is actively replicating in beak tissue.
Results:
Poecivirus was detected in 28/28 (100%) individuals with AKD, but only 9/96 (9.4%) asymptomatic individuals with apparently normal beaks (p < 0.0001). We found that cloacal swabs are the most sensitive of these sample types for detecting Poecivirus in birds with AKD, but that buccal swabs should be combined with cloacal swabs in evaluating the infection status of asymptomatic birds. Finally, we used both in situ hybridization and a strand-specific expression assay to localize Poecivirus to beak tissue of AKD-positive individuals and to provide evidence of active viral replication.
Conclusion:
The data presented here show a strong, statistically significant relationship between Poecivirus infection and AKD, and provide evidence that Poecivirus is indeed an avian virus, infecting and actively replicating in beak tissue of AKD-affected BCCH. Taken together, these data corroborate and extend the evidence for a potential causal association between Poecivirus and AKD in the black-capped chickadee. Poecivirus continues to warrant further investigation as a candidate agent of AKD.
In seabirds, diet and feeding methods are related to the species morphology (Croxall, Evans, & Schreiber, 1984). Species that feed on living, mobile resources rely on a fully operational beak to efficiently seize, kill and swallow their prey. This is particularly important to diving species, such as penguins, that are highly time constrained when searching for prey at depth—as air-breathing predators, penguins must maximise their feeding efficiency during their deep foraging dives (Wilson & Wilson, 1990). This is why the observation of free-ranging penguins with physical abnormalities in good body condition is so rare. Here we report a highly unusual observation of a premoult adult king penguin ( Aptenodytes patagonicus Miller) in good body condition with a highly anomalous beak.
Unlabelled:
Avian keratin disorder (AKD), characterized by debilitating overgrowth of the avian beak, was first documented in black-capped chickadees (Poecile atricapillus) in Alaska. Subsequently, similar deformities have appeared in numerous species across continents. Despite the widespread distribution of this emerging pathology, the cause of AKD remains elusive. As a result, it is unknown whether suspected cases of AKD in the afflicted species are causally linked, and the impacts of this pathology at the population and community levels are difficult to evaluate. We applied unbiased, metagenomic next-generation sequencing to search for candidate pathogens in birds affected with AKD. We identified and sequenced the complete coding region of a novel picornavirus, which we are calling poecivirus. Subsequent screening of 19 AKD-affected black-capped chickadees and 9 control individuals for the presence of poecivirus revealed that 19/19 (100%) AKD-affected individuals were positive, while only 2/9 (22%) control individuals were infected with poecivirus. Two northwestern crows (Corvus caurinus) and two red-breasted nuthatches (Sitta canadensis) with AKD-consistent pathology also tested positive for poecivirus. We suggest that poecivirus is a candidate etiological agent of AKD.
Importance:
Avian keratin disorder (AKD) is an increasingly common disease of wild birds. This disease, characterized by beak overgrowth, was first described in the late 1990s and has been spreading rapidly both geographically and in terms of host species affected. AKD decreases host fitness and can be fatal. However, the cause of the disease has remained elusive, and its impact on host populations is poorly understood. We found a novel and divergent picornavirus in 19/19 AKD-affected black-capped chickadees that we examined but in only 2/9 control cases. We also found this virus in 4 individuals of 2 other passerine species that exhibited symptoms consistent with AKD. Our data suggest that this novel picornavirus warrants further investigation as the causative agent of AKD.
Juvenile Black-legged Kittiwakes Rissa tridactyla with deformed bills and feet were observed in the Barents Sea in 1996, first while passing between Franz Josef Land and Novaya Zemlya on 21-24 July (at least 10 birds) and then off the West Coast of Svalbard 20-21 September (at least 2 birds). Deformities were manifest as prolonged upper or lower mandible, hooked or crocked upper mandible, crossed bill and clubfeet. This paper reports the circumstances of the observations and discusses possible causes. Among the possible causes are nutritional deficiencies, epizootic events, environmental pollutants (persistent organic pollutants, heavy metals or radioactivity), or combinations of these.
Bill function is highly specialised for foraging and preening, and deformations can compromise such behaviours, affecting individual
birds’ health and nutritional status (Van Hemert & Handel 2010)
and even causing mortality (Casaux 2004, Marti et al. 2008).
Such deformities can be the result of genetic defects, deficient
diet, disease, injuries and/or pollution (Pomeroy 1962, Giberston
et al. 1976, Kuiken et al. 1999, Buckle et al. 2014, Handel & Van
Hemert 2015). Deformities have been recorded in various seabirds,
including Southern Giant Petrel Macronectes giganteus (Marti et al.
2008), Antarctic Cormorant Phalacrocorax bransfieldensis (Casaux
2004), Black-legged Kittiwake Rissa tridactyla (Kylin 2005), and
Common Tern Sterna hirundo (Gochfeld 1975). There have also
been records of bill deformities in several penguin species (Table 1).
We provide the first records of bill deformities for three additional
penguin species: Adélie, African and Northern Rockhopper, as well
as the first for the genera Spheniscus and Eudyptes.
Aim:
To investigate an outbreak of severe craniofacial deformity in yellow-eyed penguin (Megadyptes antipodes, hōiho) chicks at a single breeding site on the Otago Peninsula in the South Island of New Zealand.
Methods:
Morbidity and mortality of yellow-eyed penguins breeding on the coastal regions of Otago was monitored from November 2008 to March 2009. Dead chicks and unhatched eggs were recovered and examined. Between October and December 2008 32 eggs were recorded at 17 nests in the Okia Reserve. Eleven chicks survived to about 90 days of age, of which eight were found to have moderate to severe craniofacial deformity. The six most severe chicks were subject to euthanasia and examined in detail at necropsy, and the remaining two affected chicks were released to the wild after a period of care in a rehabilitation centre. Post-mortem samples were analysed for inorganic and organic toxins.
Results:
The six deformed chicks all had severe shortening of the mandible and maxilla by 20-50 mm. The rostral and caudal regions of the skull were approximately 40 and 80% of normal length, respectively. Other, more variable lesions included cross bill deformity, malformed bill keratin, microphthalmia with misshapen scleral ossicles and oral soft tissue excess thought to be secondary to bony malformations. During the same year, mild sporadic bill deformities were also reported in 10 unrelated chicks from >167 chicks at other breeding sites on the southern Otago coast. Concentrations of organic toxins and heavy metals in body tissues from affected chicks were apparently similar to those in unaffected chicks on other beaches.
Conclusions:
No cause of this outbreak of craniofacial deformity could be established although the high prevalence at a single site suggests that it was due to an unidentified local teratogen.
A large number of beak deformities of unknown etiology have recently been reported in Black-capped Chickadees (Poecile atricapillus) and other resident avian species in Alaska. We investigated the potential association between diet and beak deformities. We analyzed carbon (delta C-13) and nitrogen (delta N-15) isotopes in whole blood of Black-capped Chickadees captured at three semi-urban sites in south-central Alaska. For dietary analysis, we included natural foods (arthropods, seeds, and berries) and anthropogenic items commonly provided in bird feeders (sunflower seeds, peanut butter, and suet). Blood samples from individuals with beak deformities exhibited lower delta N-15 values and more variable delta C-13 values than birds with normal beaks. Isotopic values of blood also differed by location for both carbon and nitrogen, but we did not detect a difference in natural dietary items across the three sites. Contributions of individual diet items differed between birds with and without beak deformities, a pattern that likely reflected reduced function of the beak. Affected birds generally consumed fewer arthropods and sunflower seeds and more peanut butter and natural seeds and berries. Although some individuals with beak deformities relied heavily on feeder foods, we did not find evidence of an anthropogenic food source shared by all affected birds. In addition, dietary differences were most pronounced for moderately to severely affected birds, which suggests that these differences are more likely to be a consequence than a cause of deformities. Received 8 March 2012, accepted 19 May 2012.
Six published case reports of nutritional secondary hyperparathyroidism are described occurring in different species of juvenile wild birds worldwide. Gross skeletal deformities are characterised by fractures and curvature of the long bones and beak resulting from an altered calcium/phosphorus ratio in the blood. The histopathologic diagnosis is osteodystrophia fibrosa and parathyroid gland hyperplasia. Deficiency of vitamin D is implicated in the two instances in which this was measured. Environmental factors include: decreased biodiversity of food sources, surface water pollution, seasonal conditions affecting food and exposure to UV light, and sub-lethal exposure to xenobiotics. Evidence is presented on the possible role of xenobiotics in the pathogenesis.
Changes in the frequency of individuals with gross abnormalities can be used as an indicator of changes in the occurrence of biologically significant levels of developmental toxicants in the habitats of natural populations. The precise nature of the defects and their relative distribution can often provide clues as to the type of contamination. Such inferences clearly require baseline data on the frequency of such deformities, and that is the purpose of this paper. For Mid-continent lesser snow geese (Chen caerulescens caerulescens) nesting at La Pérouse Bay, the current rate of gross external abnormalities among embryos and near-hatch goslings at hatch is 3.937 × 10−4 per egg (95% confidence limits 1.7053 × 10−4 to 6.507 × 10−4) and is consistent with estimates made for other species in minimally or uncontaminated habitats. Among the abnormal specimens, however, the relative distribution of defects of the beak and eye is not consistent with rates of spontaneous abnormalities reported for chickens. If the higher relative frequency of beak defects persists in future or other geographic samples displaying overall levels of abnormalities higher than our benchmark, then contaminants acting as type 1 teratogens should be suspected. Of the compounds this increasingly agriculturally dependent species is exposed to, insecticides rather than herbicides would be the more likely class of candidates. We urge others who may have similar data on other species to make it more broadly available since such benchmarks are crucial for the use of birds as bioindicators of environmental conditions. To that end, we offer our web site as a place where data on and images of abnormal specimens can be posted and, within certain constraints, will curate submitted specimens.
L'apparition soudaine d'un groupe important d'animaux comportant de graves anomalies peut témoigner d'un changement significatif dans un écosystème. Nous décrivons une concentration inhabituelle de difformités du bec qui semblent avoir surgit rapidement en Alaska et qui s'étendent maintenant vers le sud le long de la côte du Pacifique. En Alaska, nous avons documenté, principalement au cours de la dernière décennie, 2 160 individus de Poecile atricapillus et 435 individus de 29 autres espèces d'oiseaux dotées d'un bec manifestement surdéveloppé et souvent croisé. La prévalence annuelle des anomalies du bec parmi les adultes de P. atricapillus dans le centre-sud de l'Alaska variait entre 3,6 % et 9,7 % et atteignait en moyenne 6,5 ± 0,5 % entre 1999 et 2008. Seulement 0,05 ± 0,05 % des oisillons et 0,3 ± 0,2 % des juvéniles âgés de moins de 6 mois possédaient des becs anormaux, ce qui suggère qu'il s'agit soit d'un développement latent ou d'une condition acquise. Nous avons documenté 80 cas pour lesquels un individu de P. atricapillus capturé avec un bec apparemment normal était subséquemment recapturé avec une anomalie du bec, et 8 cas pour les quels une difformité du bec n'était plus détectée lors d'une recapture. L'autopsie et l'histopathologie d'un échantillon d'individus affectés d'une anomalie n'ont fourni aucune preuve concluante de l'étiologie de cette condition. Les difformités semblent affecter principalement la couche de kératine du bec et peuvent résulter d'une croissance anormalement rapide de la rhamphothèque. Certains oiseaux affectés présentaient aussi des lésions dans d'autres tissus kératinisés de la peau, des pattes, des pieds, des serres et des plumes, ce qui peut représenter un trouble systémique ou des conditions secondaires. Des études complémentaires sont actuellement en cours afin d'identifier des indices diagnostiques et la cause sous-jacente de ce trouble de la kératine aviaire.
Two hundred Large White turkey hens were fed diets varying in vitamin D3 supplementation (300, 900, or 2700 IU/kg feed) from day-old to 37 weeks of age. Hens receiving 300 IU vitamin D3/kg feed produced fewer eggs, which were lighter in weight and had thinner shells than those laid by hens receiving the higher levels of vitamin D3. Fertility was not affected by treatment; however, hatchability of eggs from hens fed 300 IU vitamin D3/kg feed was reduced by 48% from that of hens fed the two higher levels. A shortened upper mandible, which was detected in embryos during Week 4 of incubation, accounted for approximately 10% of the total embryo mortality and 49.5% of the embryo mortality, during Week 4. It appeared that hens fed the low vitamin D3 did not have adequate amounts of the vitamin to transport to the egg for normal embryonic development.
Data on natal philopatry were obtained for Cory's Shearwaters (Calonectris diomedea) on an island in the western Mediterranean Sea. Males visited or bred near where they had been reared more often than females, and returned to breed in their natal colony in higher proportion than did females. Females changed subcolony more often than males did.
A large cluster of beak abnormalities among black-capped chickadees (Poecile atricapillus) in Alaska raised concern about underlying environmental factors in this region. We analyzed metals and trace elements, organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-dioxins and polychlorinated dibenzofurans (PCDD-Fs) in adults, nestlings, and eggs of the affected population; we also tested local bird seed for OC pesticides. Our results offered no support for the hypothesis that selenium or any other inorganic element was responsible for beak deformities among chickadees, but some evidence that OC compounds may be contributing factors. Adults with beak deformities had an elevated level of chromosomal damage, which was correlated with lipid level and concentrations of several OC compounds. Multivariate analyses of pesticides and PCBs did not distinguish abnormal vs. normal adults, but subsequent univariate analysis demonstrated higher concentrations of heptachlor epoxide and PCB-123 in abnormal adults. Concentrations of all OC compounds were low and none is known to cause beak or keratin abnormalities. Patterns of PCB congener concentrations differed between nestlings with normal and abnormal parents. Eggs from clutches with low hatchability had higher concentrations of hexachlorobenzene and PCDD-Fs than those with high hatching success, and hexachlorobenzene was found in seeds. Additional testing for PCDD-Fs, polycyclic aromatic hydrocarbons, and other emerging contaminants, including brominated compounds, is needed to rule out environmental contaminants as a cause of beak deformities in chickadees in Alaska. Environ Toxicol Chem © 2014 SETAC
Avian integument is thin, elastic, and loosely attached to the body, giving birds the freedom of movement needed for flight. Its epidermis is both keratinized and lipogenic, and the skin as a whole acts as a sebaceous secretory organ. The skin is covered by feathers over most of the body, but many birds show colored bare skin or integumentary outgrowths on the head and neck. Heavily cornified epidermis covers the beak, claws, spurs, and the scales on the legs and feet. These structures (except the back of the leg and underside of the foot) contain beta-keratin like that in reptilian scales. Most birds have sebaceous secretory glands at the base of the tail and in the ear canals. Feathers are the most numerous, elaborate, and diverse of avian integumentary derivatives. Their diversity is due to the possibilities inherent in their basic plan of a shaft with two orders of branches and the use of modified beta-keratin as a strong, light, and plastic building material. The evolution of feathers in birds has been accompanied by the development of complex systems for producing colors and patterns, the innovations of feather arrangement and follicles with their musculature and innervation, and the process and control of molting.
Eight of 20 newly hatched double-crested cormorants (Phalacrocorax auritus), captured at Doré Lake (Saskatchewan, Canada) and raised in captivity, developed malformed bills when they were 2 to 3 weeks old. Malformation was characterized by abnormal flexure and rotation of the maxilla and mandible, resulting in a crossed bill. By radiography, the premaxillary and dental bones were misshapen. Morphologically similar malformed bills in free-living cormorants have been attributed to exposure to polyhalogenated aromatic hydrocarbons. However, the concentrations of total PCBs in the livers of these captive cormorants with malformed bills and in their diet were lower than have been previously associated with such malformations and were considered too low to have been the cause. The bill malformations may have been caused by deficiency of vitamin D3, because the cormorants were kept indoors without exposure to ultraviolet light and were fed frozen fish that may have been deficient in this vitamin.
Philornis downsi (Diptera: Muscidae), in Darwin's small ground finch, Geospiza fuliginosa (Passeriformes: Emberizidae)
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