E. V. Fedonenko, O. N. Marenkov
Spreading, spatial distribution, and morphometric characteristics of the pumpkinseed sunfish Lepomis gibbosus (Centrarchidae, Perciformes) in the Zaporozhye Reservoir
Russian Journal of Biological Invasions July 2013, Volume 4, Issue 3, pp 194-199
The data on distribution, biology, and ecology of the pumpkinseed sunfish in the basin of the Zaporozhye Reservoir are presented. On the basis of morphometric studies and available published data, a comparative analysis of plastic features of the outer morphology of the pumpkinseed sunfish in the Zaporozhye Reservoir compared to fish from other water bodies of Ukraine, Slovenia, and Canada is performed.
A. Yu. Oleinikov
Distribution of native and introduced semiaquatic mammals in Sikhote-Alin
Russian Journal of Biological Invasions July 2013, Volume 4, Issue 3, pp 180-189
Data on current habitat ranges of five species of semiaquatic mammals are given in the article. The data were collected in various parts of Sikhote-Alin in 2002–2012. Four of the species, American mink (Neovison vison Schreb.), muskrat (Ondatra zibethicus L.), Eurasian beaver (Castor fiber L.), and Canadian beaver (C. canadensis Kuhl), are introduced. A native species is the otter (Lutra lutra L.). The stages of introduction and peculiarities of distribution of the semiaquatic species populations are described. The spatial distribution of the animals on the Obor and Durmin rivers selected as the model ones by us previously is analyzed (Oleinikov, 2007). The middle reaches of these rivers demonstrate the greatest variety of semiaquatic species, and their density is maximal in the lower reaches, which is mainly due to the muskrat. The spatial dissociation as a mechanism of alleviation of interspecific relationships is revealed.
Zootaxa 3717 (3): 345–358 (30 Sept. 2013)
A new species of lizard genus Potamites from Ecuador (Squamata, Gymnophthalmidae)
MARCO ALTAMIRANO-BENAVIDES, HUSSAM ZAHER, LUCIANA LOBO, FELIPE GOBBI GRAZZIOTIN, PEDRO MURILO SALES NUNES & MIGUEL TREFAUT RODRIGUES
Potamites flavogularis sp. nov. is described from the Napo and Tungurahua Provinces around 1800 m elevation in eastern Ecuador. The new species is closely related, sibling, and sympatric to Potamites cochranae to which it has been previously confused. It is characterized by the absence of isolated basal flounces of spines and presence of calcareous spinules on flounces of the hemipenis, a short (1,30–1,41 times SVL) and slightly compressed tail without tubercles, tympanum slightly recessed, subimbricate ventral scales, lateral body scales lacking conspicuous enlarged tubercles, four longitudinal rows
of dorsal tubercles, 6 transverse series of ventral scales, absence of intercalated scales along sides of tail, and absence of tubercles on sides of neck and gular regions. Like their congeners, the new species was found close to vegetation surrounding streams in primary and secondary forests.
F. Boray Tek, Flavio Cannavo, Giuseppe Nunnaric, İzzet Kale, Robust Localization and Identification of African Clawed Frogs in Digital Images, Ecological Informatics, Available online 29 September 2013, ISSN 1574-9541, http://dx.doi.org/10.1016/j.ecoinf.2013.09.005.
We study automatic localization and identification of African clawed frogs (Xenopus Laevis sp.) in digital images taken in a laboratory environment. We propose a novel and stable frog body localization and skin pattern window extraction algorithm. We show that it compensates scale and rotation changes very well. Moreover, it is able to localize and extract highly overlapping regions (pattern windows) even in the cases of intense affine transformations, blurring, Gaussian noise, and intensity transformations. The frog skin pattern (i.e. texture) provides a unique feature for the identification of individual frogs. We investigate the suitability of five different feature descriptors (Gabor filters, area granulometry, HoG, 1 Histogram of gradients. dense SIFT, 2 Scale invariant feature transform. and raw pixel values) to represent frog skin patterns. We compare the robustness of the features based on their identification performance using a nearest neighbor classifier. Our experiments show that among five features that were tested, the best performing feature against rotation, scale, and blurring modifications was the raw pixel feature, whereas the SIFT feature was the best performing one against affine and intensity modifications.
Bonizzoni, S., Furey, N. B., Pirotta, E., Valavanis, V. D., Würsig, B. and Bearzi, G. (2013), Fish farming and its appeal to common bottlenose dolphins: modelling habitat use in a Mediterranean embayment. Aquatic Conserv: Mar. Freshw. Ecosyst.. doi: 10.1002/aqc.2401
Common bottlenose dolphins Tursiops truncatus interact with fish farms in the Mediterranean Sea. These interactions were investigated in a Greek bay by incorporating multiple geographic, bathymetric, oceanographic, and anthropogenic variables.Generalized additive models (GAMs) and generalized estimation equations (GEEs) were used to describe dolphin presence. Visual surveys were conducted over 2909 km under favourable viewing conditions that included 54 dolphin group follows for 457 km. Sea surface temperature (SST) and chlorophyll-a (Chl-a) data were obtained from remote sensing imagery, and distances to sources of human influences including fish farms, a ferro-nickel plant, and a slag disposal area were calculated within a geographic information system (GIS).Bottlenose dolphins were encountered mainly in the south-eastern portion of the study area, and occurrence was not clearly related to SST and Chl-a, nor the ferro-nickel plant or nearby slag disposal area.Dolphin occurrence generally increased within 20 km of fish farms, with four farms and dolphins displaying a positive relationship, seven no clear relationship, and two a negative one.While it is likely that uneaten food and other detritus attract dolphin prey, individual farms (or clusters of farms) clearly had a different appeal. The proximity of the ferro-nickel plant and slag disposal area to ‘attractive’ fish farms could compromise dolphin health, but physiological data are unavailable.The modelling of multiple variables allowed for a description of dolphin habitat use and attraction to some fish farms. More such data analysed in similar manner would be instructive for other areas where marine mammals and fish farms co-occur.
Muir, A. M., Vecsei, P., Power, M., Krueger, C. C. and Reist, J. D. (2013), Morphology and life history of the Great Slave Lake ciscoes (Salmoniformes: Coregonidae). Ecology of Freshwater Fish. doi: 10.1111/eff.12098
The taxonomy of the North American ciscoes (Salmoniformes: Coregonidae) remains unresolved. We provide the first comprehensive description of the Great Slave Lake ciscoes. Our analysis supports the hypothesis that the Great Slave Lake cisco complex includes at least two nominate species (Coregonus artedi and Coregonus sardinella) and an adfluvial C. artedi morph that is distinct from its lacustrine conspecific in terms of life history, morphology, age, growth and mortality. Coregonus sardinella has previously been identified from Great Slave Lake, but we provide the first comprehensive description of this species in the lake and confirm a significant range extension for the species. The lacustrine C. artedi differs little from descriptions throughout its range. In addition to these three ciscoes, linear phenotypic traits, gillraker number and morphology, and growth data support the possible occurrence of two other, less-distinct morphs, the big-eye cisco and a shortjaw-like morph Coregonus zenithicus. Although the big-eye morph was not identified by body shape and linear phenotypic measures, it was visually identified on the basis of differences in traditional phenotypic proportions, such as orbital length, paired fin lengths, head and gillraker morphology expressed as thousands of standard length and showed different age and growth structure compared with the other lacustrine cisco morphs. Coregonus zenithicus was distinguished visually and by a statistical model of linear phenotypic traits as well as by gillraker number and morphology. Identifying, characterising and managing locally adapted cisco morphs that reflect important ecological and bioenergetic linkages are critical to conserving the ecological integrity of northern ecosystems.
Fleming, P. A., Anderson, H., Prendergast, A. S., Bretz, M. R., Valentine, L. E. and Hardy, G. E. StJ. (2013), Is the loss of Australian digging mammals contributing to a deterioration in ecosystem function?. Mammal Review. doi: 10.1111/mam.12014
Despite once being described as common, digging mammal species have been lost from the Australian landscape over the last 200 years. Around half of digging mammal species are now extinct or under conservation threat, and the majority of extant species have undergone marked range contractions.Our aim is to identify the role of digging mammals in ecosystem processes throughout Australia. We highlight how the actions of digging mammals are vital for maintaining ecosystem functioning and how their extirpation has led to loss of ecosystem functions. A review of the literature indicates that many aspects of the influence of bioturbation on ecosystem functioning have been studied. The role of digging mammals in arid and semi-arid zones has been previously established. We collate and review a broader scope of studies, including those carried out in the mesic woodlands and forests of Australia. We identify roles of digging mammals in the context of ecosystem functioning and conservation management.Bioturbation significantly alters soil processes, increasing soil turnover and altering the chemical and structural properties of soil. Greater water infiltration and decreased surface run-off and erosion alter soil hydrophobicity and increase soil moisture. Diggings capture organic matter, provide habitat for a diversity of microscopic and macroscopic organisms, and increase nutrient cycling. Mycophagous mammals disperse fungi (e.g. mycorrhizae), while all diggings can create suitable sites for fungal growth. Diggings also capture plant seeds, increasing seedling germination, recruitment and plant growth. The overall effect of mammal diggings is therefore increased plant vigour and resilience, increased biodiversity and consequently improved ecosystem functioning.We propose that the loss of digging mammals has contributed to the deterioration of ecosystems in Australia. Recognising the roles of digging mammals will inform potential management options such as species translocations or reintroductions.
Resolving lost herbivore community structure using coprolites of four sympatric moa species (Aves: Dinornithiformes)
Jamie R. Wood, Janet M. Wilmshurst, Sarah J. Richardson, Nicolas J. Rawlence, Steven J. Wagstaff, Trevor H. Worthy, and Alan Cooper
PNAS 2013 ; published ahead of print September 30, 2013, doi:10.1073/pnas.1307700110
Knowledge of extinct herbivore community structuring is essential for assessing the wider ecological impacts of Quaternary extinctions and determining appropriate taxon substitutes for rewilding. Here, we demonstrate the potential for coprolite studies to progress beyond single-species diet reconstructions to resolving community-level detail. The moa (Aves: Dinornithiformes) of New Zealand are an intensively studied group of nine extinct herbivore species, yet many details of their diets and community structuring remain unresolved. We provide unique insights into these aspects of moa biology through analyses of a multispecies coprolite assemblage from a rock overhang in a montane river valley in southern New Zealand. Using ancient DNA (aDNA), we identified 51 coprolites, which included specimens from four sympatric moa species. Pollen, plant macrofossils, and plant aDNA from the coprolites chronicle the diets and habitat preferences of these large avian herbivores during the 400 y before their extinction (∼1450 AD). We use the coprolite data to develop a paleoecological niche model in which moa species were partitioned based on both habitat (forest and valley-floor herbfield) and dietary preferences, the latter reflecting allometric relationships between body size, digestive efficiency, and nutritional requirements. Broad ecological niches occupied by South Island giant moa (Dinornis robustus) and upland moa (Megalapteryx didinus) may reflect sexual segregation and seasonal variation in habitat use, respectively. Our results show that moa lack extant ecological analogs, and their extinction represents an irreplaceable loss of function from New Zealand’s terrestrial ecosystems.
Ros Gloag, Vanina D. Fiorini, Juan C. Reboreda, Alex Kacelnik, The wages of violence: mobbing by mockingbirds as a frontline defence against brood-parasitic cowbirds, Animal Behaviour, Available online 1 October 2013, ISSN 0003-3472, http://dx.doi.org/10.1016/j.anbehav.2013.09.007.
For many hosts of brood-parasitic birds, their frontline of defence is to mob adult parasites that approach the nest. Mobbing is commonly interpreted as an adaptation to prevent the parasite from laying, although to date evidence of this is indirect or anecdotal. We investigated the effectiveness of mobbing by chalk-browed mockingbirds, Mimus saturninus, as a defence against their parasite, the shiny cowbird, Molothrus bonariensis, using videos of 480 naturally occurring cowbird nest visits and other direct observations. Mockingbirds only occasionally prevented cowbirds from reaching the nest or from laying once in it. More often, cowbirds were able to deposit an egg, aided by their agile flight, rapid laying, endurance of mobbing and, in some cases, opportunistic timing, whereby they approached nests when mockingbirds were distracted in battle with other cowbirds. Adult parasites present a second threat to hosts, however, in that they try to damage or remove host eggs prior to laying their own. We found that mobbing at the nest significantly reduced the likelihood that cowbirds broke a mockingbird egg during their visit, despite almost all mobbed visits concluding with a cowbird laying an egg. In this host therefore, the benefit of mobbing must be assessed by two independent measures: prevention of egg laying by the parasite and loss of their own eggs. As mockingbird eggs that survive a cowbird’s visit intact can go on to fledge from parasitized broods, we expect strong selection for mobbing as an antiparasite defence in this host, even though it largely fails to prevent parasitism itself.
I.S. Pauwels, A.M. Mouton, J.M. Baetens, S. Van Nieuland, B. De Baets, P.L.M. Goethals, Modelling a pike (Esox lucius) population in a lowland river using a cellular automaton, Ecological Informatics, Volume 17, September 2013, Pages 46-57, ISSN 1574-9541, http://dx.doi.org/10.1016/j.ecoinf.2012.04.003.
Cellular automata (CAs) allow for transparent modelling of complex systems based on simple transition rules and are flexible in incorporating individual differences and local interactions. They may therefore be particularly suited to answer river management questions that could not be addressed by existing habitat suitability models, such as the optimal distance between spawning grounds. This study explores the usability of CAs for spatio-temporal modelling of a pike population to support river management. Specifically, we evaluated the usability of the CA model by analyzing its sensitivity to three model parameters: the number of pike in the grid, the initial pike distribution and the grid resolution. The model includes habitat characteristics and basic expert knowledge on the ecology of pike and was tested on a 10km stretch of the river Yser in Flanders (Belgium). Simulation results showed that the model converged to a realistic pike distribution over the study area only at high pike density and low grid resolution, irrespective of the initial pike distribution. Pike density and grid resolution affected the sensitivity to the initial pike distribution in the grid. Specifically, the sensitivity was high at low pike density and high grid resolution, and absent when pike density was high. This analysis indicated that initial conditions and cell size may have a severe impact on the model output, illustrating the importance of firstly analyzing this impact before conducting further analyses. Depending on the outcome of such analyses, CAs can be a promising modelling technique to evaluate and predict the effect of river restoration on pike populations.
Blancher, P. 2013. Estimated number of birds killed by house cats (Felis catus) in Canada. Avian Conservation and Ecology 8(2): 3.
Predation by house cats (Felis catus) is one of the largest human-related sources of mortality for wild birds in the United States and elsewhere, and has been implicated in extinctions and population declines of several species. However, relatively little is known about this topic in Canada. The objectives of this study were to provide plausible estimates for the number of birds killed by house cats in Canada, identify information that would help improve those estimates, and identify species potentially vulnerable to population impacts. In total, cats are estimated to kill between 100 and 350 million birds per year in Canada (> 95% of estimates were in this range), with the majority likely to be killed by feral cats. This range of estimates is based on surveys indicating that Canadians own about 8.5 million pet cats, a rough approximation of 1.4 to 4.2 million feral cats, and literature values of predation rates from studies conducted elsewhere. Reliability of the total kill estimate would be improved most by better knowledge of feral cat numbers and diet in Canada, though any data on birds killed by cats in Canada would be helpful. These estimates suggest that 2-7% of birds in southern Canada are killed by cats per year. Even at the low end, predation by house cats is probably the largest human-related source of bird mortality in Canada. Many species of birds are potentially vulnerable to at least local population impacts in southern Canada, by virtue of nesting or feeding on or near ground level, and habitat choices that bring them into contact with human-dominated landscapes where cats are abundant. Because cat predation is likely to remain a primary source of bird mortality in Canada for some time, this issue needs more scientific attention in Canada.
Biological Invasions October 2013
Why do lizards avoid weeds?
Jessica Hacking, Rickard Abom, Lin Schwarzkopf
Invasion of native habitats by exotic plants often causes reductions in faunal diversity. However, there is little direct evidence of native fauna actively avoiding invaded habitat and few quantitative studies on the mechanisms underlying such avoidance. We quantified alterations made to the composition and physical structure of an Australian tropical savanna by grader grass (Themeda quadrivalvis); an understudied invasive grass that is associated with reduced faunal abundance and diversity. We found that grader grass profoundly changed the physical structure and floral composition of tropical savanna, forming dense lawn-like monocultures unlike the native savanna. Second, we investigated the habitat preferences of small ectotherms in partially invaded habitat, using a rainbow skink (Carlia schmeltzii) as a model system and discovered that they actively avoided grader grass. Finally, we experimentally tested predictions regarding mechanisms that may have driven the avoidance of grader grass. Predation rates and food availability were not likely the cause of grader grass avoidance, because experiments using models deployed in the field showed that predation rates were higher in native grass, and collection of invertebrates in both habitats indicated that prey availability was similar. However, mesocosm experiments on habitat selection in relation to vegetation structure, along with field measures of available operative environmental temperatures, suggested that small ectotherms probably avoid grader-grass-invaded savanna due to a suboptimal thermal environment and lack of appropriate habitat structural heterogeneity.
Kajdacsi, B., Costa, F., Hyseni, C., Porter, F., Brown, J., Rodrigues, G., Farias, H., Reis, M. G., Childs, J. E., Ko, A. I. and Caccone, A. (2013), Urban population genetics of slum-dwelling rats (Rattus norvegicus) in Salvador, Brazil. Molecular Ecology. doi: 10.1111/mec.12455
Throughout the developing world, urban centres with sprawling slum settlements are rapidly expanding and invading previously forested ecosystems. Slum communities are characterized by untended refuse, open sewers and overgrown vegetation, which promote rodent infestation. Norway rats (Rattus norvegicus) are reservoirs for epidemic transmission of many zoonotic pathogens of public health importance. Understanding the population ecology of R. norvegicus is essential to formulate effective rodent control strategies, as this knowledge aids estimation of the temporal stability and spatial connectivity of populations. We screened for genetic variation, characterized the population genetic structure and evaluated the extent and patterns of gene flow in the urban landscape using 17 microsatellite loci in 146 rats from nine sites in the city of Salvador, Brazil. These sites were divided between three neighbourhoods within the city spaced an average of 2.7 km apart. Surprisingly, we detected very little relatedness among animals trapped at the same site and found high levels of genetic diversity, as well as structuring across small geographical distances. Most FST comparisons among sites were statistically significant, including sites <400 m apart. Bayesian analyses grouped the samples in three genetic clusters, each associated with distinct sampling sites from different neighbourhoods or valleys within neighbourhoods. These data indicate the existence of complex genetic structure in R. norvegicus in Salvador, linked to the heterogeneous urban landscape. Future rodent control measures need to take into account the spatial and temporal linkage of rat populations in Salvador, as revealed by genetic data, to develop informed eradication strategies. Zootaxa 3717 (4): 469–497 (1 Oct. 2013)
Taxonomic revision of Myrmeciza (Aves: Passeriformes: Thamnophilidae) into 12 genera based on phylogenetic, morphological, behavioral, and ecological data
MORTON L. ISLER, GUSTAVO A. BRAVO & ROBB T. BRUMFIELD
A comprehensive molecular phylogeny of the family Thamnophilidae indicated that the genus Myrmeciza (Gray) is not
monophyletic. Species currently assigned to the genus are found in three of the five tribes comprising the subfamily Thamnophilinae. Morphological, behavioral, and ecological character states of species within these tribes and their closest relatives were compared to establish generic limits. As a result of this analysis, species currently placed in Myrmeciza are assigned to Myrmeciza and eleven other genera, four of which (Myrmelastes Sclater, Myrmoderus Ridgway, Myrmophylax Todd, and Sipia Hellmayr) are resurrected, and seven of which (Ammonastes, Ampelornis, Aprositornis, Hafferia, Inundicola, Poliocrania, and Sciaphylax) are newly described.
Carol E. Johnston, Andrew R. Henderson, Wendi W. Hartup
Precipitous decline and conservation of Slackwater Darter (Etheostoma boschungi) in tributaries of the Tennessee River, Tennessee and Alabama
Biodiversity and Conservation October 2013
Etheostoma boschungi (Slackwater Darter) is a migratory fish species endemic to tributaries of the Tennessee River. Although the distribution of this species was historically disjunct and limited, current data suggest that the species is suffering a decline in both distribution and abundance, resulting in critically low population levels. Data collected over a 10-year period demonstrate an approximate 45 % distributional decline relative a previous survey. In addition, numbers of individuals collected at breeding sites has also declined during this time period. Detectability for sites with repeated sampling effort suggest that even where the species persists, it may be in numbers too low for detection with just one effort. Factors affecting persistence of Slackwater Darters may include passage barriers, such as culverts and loss of connectivity to flooded breeding sites due to channel incision, but data on the effects of these environmental factors are largely lacking.
Christina M. Schmidt, Wendy R. Hood, Bone loss is a physiological cost of reproduction in white-footed mice (Peromyscus leucopus), Mammalian Biology – Zeitschrift für Säugetierkunde, Available online 1 October 2013, ISSN 1616-5047, http://dx.doi.org/10.1016/j.mambio.2013.09.003.
Investment in offspring production often requires the mobilization of endogenous resources, a strategy that may negatively impact maternal condition. In mammals, skeletal ossification in growing offspring requires a large investment of calcium by mothers, and bone loss has been described in several species as a means of supporting this demand. Although bone loss can have adverse effects on the mother, its potential role in a reproductive trade-off has not been addressed. Using white-footed mice (Peromyscus leucopus), we tested the effect of dietary calcium availability on maternal skeletal condition during reproduction to assess if calcium availability drives a trade-off between maternal skeletal condition and offspring production. We provided mice with a low-calcium or standard diet and monitored reproductive output along with changes in bone mineral density and bone resorption (via serum concentrations of pyridinoline crosslinks) throughout reproduction. Reproductive performance was not impaired by low calcium intake. Reproductive females on the low-calcium diet showed a significant reduction in bone mineral density relative to reproductive females consuming the standard diet and non-reproductive mice consuming the low-calcium diet, but no difference in bone resorptive activity. Our results suggest that when dietary calcium is limited white-footed mice reproduce at the expense of their skeletal condition, and may do so by limiting bone mineral accretion relative to resorption.
Röper, K.M., Scheumann, M., Wiechert, A.B., Nathan, S., Goossens, B., Owren, M.J. and Zimmermann, E. (2013), Vocal acoustics in the endangered proboscis monkey (Nasalis larvatus). Am. J. Primatol.. doi: 10.1002/ajp.22221
The endangered proboscis monkey (Nasalis larvatus) is a sexually highly dimorphic Old World primate endemic to the island of Borneo. Previous studies focused mainly on its ecology and behavior, but knowledge of its vocalizations is limited. The present study provides quantified information on vocal rate and on the vocal acoustics of the prominent calls of this species. We audio-recorded vocal behavior of 10 groups over two 4-month periods at the Lower Kinabatangan Wildlife Sanctuary in Sabah, Borneo. We observed monkeys and recorded calls in evening and morning sessions at sleeping trees along riverbanks. We found no differences in the vocal rate between evening and morning observation sessions. Based on multiparametric analysis, we identified acoustic features of the four common call-types “shrieks,” “honks,” “roars,” and “brays.” “Chorus” events were also noted in which multiple callers produced a mix of vocalizations. The four call-types were distinguishable based on a combination of fundamental frequency variation, call duration, and degree of voicing. Three of the call-types can be considered as “loud calls” and are therefore deemed promising candidates for non-invasive, vocalization-based monitoring of proboscis monkeys for conservation purposes.
Sousa, J., Vicente, L., Gippoliti, S., Casanova, C. and Sousa, C. (2013), Local knowledge and perceptions of chimpanzees in Cantanhez National Park, Guinea-Bissau. Am. J. Primatol.. doi: 10.1002/ajp.22215
Our study concerns local knowledge and perceptions of chimpanzees among farming communities within Cantanhez National Park, Guinea-Bissau. We submitted a survey questionnaire to 100 people living in four villages in the Park to enquire about their knowledge of chimpanzee ecology and human–chimpanzee interactions. Local farmers live in close contact with chimpanzees, consider them to be more similar to humans than any other species, and attribute special importance to them primarily due to expectations of tourism revenue. Interviewees‘ responses, as a function of gender, village, and age, were analyzed statistically using non-parametric tests (Mann–Whitney and Kruskal–Wallis). Age influenced responses significantly, while gender and village had no significant effect. Youngsters emphasized morphological aspects of human–chimpanzee similarities, while adults emphasized chimpanzee behavior and narratives about the shared history of humans and chimpanzees. Tourism, conservation, and crop raiding feature prominently in people’s reports about chimpanzees. Local people’s engagement with conservation and tourism-related activities is likely to allow them to manage not only the costs but also the benefits of conservation, and can in turn inform the expectations built upon tourism.
Aourir, M., Znari, M., Radi, M. and Melin, J.-M. (2013), Wild-laid versus captive-laid eggs in the black-bellied sandgrouse: Is there any effect on chick productivity?. Zoo Biol.. doi: 10.1002/zoo.21095
Because survival in captivity is a significant determinant of birds available for release and reinforcement of wild populations, we aimed to identify sources of variation in mortality to assess potential impacts of management on chick productivity. We analyzed characteristics of Black-bellied Sandgrouse eggs collected from the wild and produced by captive pairs. Wild laid-eggs and pulled captive-laid eggs were incubated artificially and all chicks were hand-reared until seven weeks of age. Wild-laid eggs were significantly bigger, heavier, and denser than captive-laid eggs which showed a higher variability in size. Fertility, embryo mortality, and fertile egg hatchability were similar for wild-laid and captive-laid eggs (67.92% vs. 68%; 15.62% vs. 15.7%, and 80.55% vs. 84.44%, respectively). There were significant positive relationships between egg weigh/volume and chick hatch weight. Mortality of chicks hatched from wild-laid eggs was much lower than that of chicks from captive-laid eggs (19.44% vs. 60.5%) during the first week after hatching, but decreased and being nil from the third week. Heavier hatchlings from captive-laid eggs exhibited higher survival rates which is not the case of hatchlings from wild-laid eggs. These latter hatchlings had higher survival rates increasing with the age of eggs in relation with the period of natural incubation. The recommended age at which wild-laid eggs could be collected is at least 13 days for full chick survivability. We concluded that in our experimental captive breeding program of the Black-bellied Sandgrouse, productivity of viable hatchlings was much better from wild-laid eggs and as later as these were collected.