Pub Date : 2010-04-22DOI: 10.2174/1874453201003010072
A. Poiani
In birds, microparasites found in both the reproductive and the digestive tracts may be transmitted through copulations via cloacal contact (male-to-female and vice versa) and/or through the seminal fluid (mainly male-to-female). Most importantly, such cloacal microparasites are affected by and may in turn affect sexual selection processes and the evolution of mating systems. Here I provide preliminary comparative evidence that at least some cloacal microparasites tend to be distributed in hosts according to the host's mating system and as broadly expected from predictions of sexual selection theory. The patterns, however, are more suggestive than conclusive. There is a non-significant trend for polyg- amy to be associated with higher richness of cloacal microparasite taxa; with body size, however, also having a positive association with both polygamy and parasite richness. Although increased sexual plumage dichromatism tends to be asso- ciated with decreased cloacal microparasite richness, indicating that secondary sexual traits may be used by sexual part- ners to discriminate between infected and uninfected individuals, qualitative trends also suggest that non-mating periods of the year tend to be associated with slightly higher levels of prevalence and richness of cloacal microparasites. Given this variability of results, it is suggested that future studies should focus on specialist sexually transmitted microbes, to be compared with more generalist one.
{"title":"Do Cloacal Pathogenic Microbes Behave as Sexually Transmitted Parasites in Birds","authors":"A. Poiani","doi":"10.2174/1874453201003010072","DOIUrl":"https://doi.org/10.2174/1874453201003010072","url":null,"abstract":"In birds, microparasites found in both the reproductive and the digestive tracts may be transmitted through copulations via cloacal contact (male-to-female and vice versa) and/or through the seminal fluid (mainly male-to-female). Most importantly, such cloacal microparasites are affected by and may in turn affect sexual selection processes and the evolution of mating systems. Here I provide preliminary comparative evidence that at least some cloacal microparasites tend to be distributed in hosts according to the host's mating system and as broadly expected from predictions of sexual selection theory. The patterns, however, are more suggestive than conclusive. There is a non-significant trend for polyg- amy to be associated with higher richness of cloacal microparasite taxa; with body size, however, also having a positive association with both polygamy and parasite richness. Although increased sexual plumage dichromatism tends to be asso- ciated with decreased cloacal microparasite richness, indicating that secondary sexual traits may be used by sexual part- ners to discriminate between infected and uninfected individuals, qualitative trends also suggest that non-mating periods of the year tend to be associated with slightly higher levels of prevalence and richness of cloacal microparasites. Given this variability of results, it is suggested that future studies should focus on specialist sexually transmitted microbes, to be compared with more generalist one.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"168 1","pages":"72-85"},"PeriodicalIF":0.0,"publicationDate":"2010-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-22DOI: 10.2174/1874453201003010021
M. Evans
Several decades of research have produced a large number of studies that examine the effects of hormones on physiology, behaviour and morphology. In the last fifteen years there has been considerable interest from evolutionary bi- ologists on the impact of hormones, especially testosterone, on aspects of physiology in particular immune function. Inter- estingly, especially given the recent attention from evolutionary biologists, the primary focus has been on determining the existence of links between hormones and other aspects of physiology or behaviour, with an emphasis on the understand- ing of mechanism. Typically though evolutionary biology focuses not on mechanism but on function - i.e. the evolution- ary explanation for why a given trait or relationship between traits exists. Evolutionary biologists would expect that if two parts of an organism's physiology were both affected by a hormone then there should be some adaptive reason why such a link exists. The fact that a hormone simultaneously influences aspects of physiology, behaviour and morphology suggests that individuals linking these traits typically benefit in someway from doing so. This paper attempts to provide some func- tional explanations for such links and proposes that testosterone may be the hormone that tips animals between 'hare-like' and 'tortoise-like' life-history strategies, with testosterone pushing individuals towards 'hare-like' strategies. If links be- tween physiological, behavioural and morphological traits exist because they benefit the organisms concerned, then we might expect different species with different ecologies to arrive at different adaptive solutions. The lack of consistency be- tween the results of similar studies in different taxa may be informing us that different optimal strategies are arrived at by different species.
{"title":"Why Does Testosterone Influence Morphology, Behaviour and Physiology?","authors":"M. Evans","doi":"10.2174/1874453201003010021","DOIUrl":"https://doi.org/10.2174/1874453201003010021","url":null,"abstract":"Several decades of research have produced a large number of studies that examine the effects of hormones on physiology, behaviour and morphology. In the last fifteen years there has been considerable interest from evolutionary bi- ologists on the impact of hormones, especially testosterone, on aspects of physiology in particular immune function. Inter- estingly, especially given the recent attention from evolutionary biologists, the primary focus has been on determining the existence of links between hormones and other aspects of physiology or behaviour, with an emphasis on the understand- ing of mechanism. Typically though evolutionary biology focuses not on mechanism but on function - i.e. the evolution- ary explanation for why a given trait or relationship between traits exists. Evolutionary biologists would expect that if two parts of an organism's physiology were both affected by a hormone then there should be some adaptive reason why such a link exists. The fact that a hormone simultaneously influences aspects of physiology, behaviour and morphology suggests that individuals linking these traits typically benefit in someway from doing so. This paper attempts to provide some func- tional explanations for such links and proposes that testosterone may be the hormone that tips animals between 'hare-like' and 'tortoise-like' life-history strategies, with testosterone pushing individuals towards 'hare-like' strategies. If links be- tween physiological, behavioural and morphological traits exist because they benefit the organisms concerned, then we might expect different species with different ecologies to arrive at different adaptive solutions. The lack of consistency be- tween the results of similar studies in different taxa may be informing us that different optimal strategies are arrived at by different species.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"3 1","pages":"21-26"},"PeriodicalIF":0.0,"publicationDate":"2010-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-04-13DOI: 10.2174/1874453201003010013
S. Harikrishnan, Karthikeyan Vasudevan, K. Sivakumar
Behavioral observations on Indian peafowl Pavo cristatus in the Shivalik landscape of North India were carried out during their mating period, between 31 March and 21 May 2006. Behaviors of peafowl were recorded using scan samples. Overall, females, sub-adult males and adult males spent different proportions of time in different activities, and the proportion of time spent on different activities varied during the mating season. Visitation by females influenced the frequency of displays by adult male Indian peafowl during this period. The study reveals that peafowl behavior in its native habitat broadly conforms to that documented from captive and introduced populations. However, there were some differences between the wild and captive populations in vocalizations, maintenance behavior and spatial distribution of adult males. Since the time spent engaging in these behaviors may affect the cost of display, these results emphasize the need to assess the signaling cost in situ where the behavior evolved.
{"title":"Behavior of Indian Peafowl Pavo cristatus Linn. 1758 During the Mating Period in a Natural Population~!2009-12-03~!2010-03-02~!2010-04-13~!","authors":"S. Harikrishnan, Karthikeyan Vasudevan, K. Sivakumar","doi":"10.2174/1874453201003010013","DOIUrl":"https://doi.org/10.2174/1874453201003010013","url":null,"abstract":"Behavioral observations on Indian peafowl Pavo cristatus in the Shivalik landscape of North India were carried out during their mating period, between 31 March and 21 May 2006. Behaviors of peafowl were recorded using scan samples. Overall, females, sub-adult males and adult males spent different proportions of time in different activities, and the proportion of time spent on different activities varied during the mating season. Visitation by females influenced the frequency of displays by adult male Indian peafowl during this period. The study reveals that peafowl behavior in its native habitat broadly conforms to that documented from captive and introduced populations. However, there were some differences between the wild and captive populations in vocalizations, maintenance behavior and spatial distribution of adult males. Since the time spent engaging in these behaviors may affect the cost of display, these results emphasize the need to assess the signaling cost in situ where the behavior evolved.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"3 1","pages":"13-19"},"PeriodicalIF":0.0,"publicationDate":"2010-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-03-09DOI: 10.2174/1874453201003010001
Claudia Wickert, D. Wallschlager, F. Huettmann
Historic information is often crucial for assessing changes and drivers for wildlife and habitat changes although it is often plagued with statistically poor quality. Here we developed three habitat models on two different scales for 1939 for the white stork (Ciconia ciconia) in the region of former East Prussia. We used a geographical information system and a statistical modeling algorithm that comes from the disciplines of machine-learning and data mining (TreeNet). The oc- currence of white stork nesting grounds is mainly defined by the variables 'distance to forest', 'distance to/density of set- tlement', 'distance to pasture' and 'distance to coastline'. The models present for the first time a quantitative predictive distribution estimate for East Prussia. They are a sound foundation but could be further improved by more data regarding the structure of the habitat and more exact spatially explicit information on the location of white stork nesting sites.
{"title":"Spatially Predictive Habitat Modeling of a White Stork (Ciconia Ciconia) Population in Former East Prussia in 1939~!2009-08-03~!2009-10-15~!2010-03-09~!","authors":"Claudia Wickert, D. Wallschlager, F. Huettmann","doi":"10.2174/1874453201003010001","DOIUrl":"https://doi.org/10.2174/1874453201003010001","url":null,"abstract":"Historic information is often crucial for assessing changes and drivers for wildlife and habitat changes although it is often plagued with statistically poor quality. Here we developed three habitat models on two different scales for 1939 for the white stork (Ciconia ciconia) in the region of former East Prussia. We used a geographical information system and a statistical modeling algorithm that comes from the disciplines of machine-learning and data mining (TreeNet). The oc- currence of white stork nesting grounds is mainly defined by the variables 'distance to forest', 'distance to/density of set- tlement', 'distance to pasture' and 'distance to coastline'. The models present for the first time a quantitative predictive distribution estimate for East Prussia. They are a sound foundation but could be further improved by more data regarding the structure of the habitat and more exact spatially explicit information on the location of white stork nesting sites.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"3 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2010-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-06DOI: 10.2174/1874453200902010029
A. Arnaiz-Villena, V. Ruíz-del-Valle, P. Gómez-Prieto, R. Reguera, C. Parga-Lozano, Ignacio Serrano-Vela
Estrildid finches are distributed throughout Africa, South Asia, Australia and neighbouring islands in the Indian and Pacific Oceans. Some specific phylogenetic and systematic debated questions have been clarified in the present study by mitochondrial cytochrome b DNA sequencing of 61 species of Estrildids and subsequent analyses of results by both Bayesian Inference and Maximum Likelihood methodologies. Our results support that Estrildids are a monophyletic group with polytomies that may have started evolving by Middle Miocene Epoch (about 16, 5 million years ago). This proposed timing is coincidental with the Fringillinae finches' radiation starting time and also with the biggest Hymalayan and Ti- betan Plateau uplift, triggered by the Indian tectonic plate strongest collision; this established present day southern Asia monsoon regime and other drastic climatic changes, like a dryer weather in Tibetan Plateau and China deserts. The Estrildid finches form a monophyletic group which includes several polytomies and comprises African, Asian and Austra- lian birds. The most ancient evolutive group comprises African (African silverbill), Asian (Indian silverbill) and Austra- lian (diamond firetail); this suggests that the whole Estrildids radiation might have originated around India.More Estrildid species will be studied in order to further establish this group phylogeography. In addition, monophyletic radiations in- clude species from different Continents. Finally, Ploceinae Genus Quelea finches is a group separate and basal from Estrildini and Viduini species in our dendrograms.
埃斯特里迪雀分布在非洲、南亚、澳大利亚和邻近的印度洋和太平洋岛屿上。本研究通过对61种Estrildids的线粒体细胞色素b DNA测序以及随后使用贝叶斯推断和最大似然方法对结果进行分析，澄清了一些特定的系统发育和系统争论问题。我们的研究结果支持Estrildids是一个具有多裂性的单系类群，可能在中新世中期(大约1650万年前)开始进化。这个时间点与Fringillinae雀科的辐射开始时间一致，也与印度构造板块最强碰撞引发的喜马拉雅高原和青藏高原最大隆升时间一致;这就建立了今天的南亚季风制度和其他剧烈的气候变化，比如青藏高原和中国沙漠的干燥天气。Estrildid雀类形成了一个单系群，包括几个多系群，包括非洲、亚洲和澳大利亚的鸟类。最古老的进化类群包括非洲(非洲银鸟)、亚洲(印度银鸟)和澳大利亚(钻石银鸟);这表明整个埃斯特里德辐射可能起源于印度附近。为了进一步建立这一类群的系统地理学，我们将对更多的Estrildid种进行研究。此外，单系辐射还包括来自不同大陆的物种。最后，在我们的树形图中，plocinae Genus Quelea finches是与Estrildini和Viduini种分离的基群。
{"title":"Estrildinae Finches (Aves, Passeriformes) from Africa, South Asia and Australia: a Molecular Phylogeographic Study","authors":"A. Arnaiz-Villena, V. Ruíz-del-Valle, P. Gómez-Prieto, R. Reguera, C. Parga-Lozano, Ignacio Serrano-Vela","doi":"10.2174/1874453200902010029","DOIUrl":"https://doi.org/10.2174/1874453200902010029","url":null,"abstract":"Estrildid finches are distributed throughout Africa, South Asia, Australia and neighbouring islands in the Indian and Pacific Oceans. Some specific phylogenetic and systematic debated questions have been clarified in the present study by mitochondrial cytochrome b DNA sequencing of 61 species of Estrildids and subsequent analyses of results by both Bayesian Inference and Maximum Likelihood methodologies. Our results support that Estrildids are a monophyletic group with polytomies that may have started evolving by Middle Miocene Epoch (about 16, 5 million years ago). This proposed timing is coincidental with the Fringillinae finches' radiation starting time and also with the biggest Hymalayan and Ti- betan Plateau uplift, triggered by the Indian tectonic plate strongest collision; this established present day southern Asia monsoon regime and other drastic climatic changes, like a dryer weather in Tibetan Plateau and China deserts. The Estrildid finches form a monophyletic group which includes several polytomies and comprises African, Asian and Austra- lian birds. The most ancient evolutive group comprises African (African silverbill), Asian (Indian silverbill) and Austra- lian (diamond firetail); this suggests that the whole Estrildids radiation might have originated around India.More Estrildid species will be studied in order to further establish this group phylogeography. In addition, monophyletic radiations in- clude species from different Continents. Finally, Ploceinae Genus Quelea finches is a group separate and basal from Estrildini and Viduini species in our dendrograms.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"54 1","pages":"29-36"},"PeriodicalIF":0.0,"publicationDate":"2009-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-20DOI: 10.2174/1874453200902010024
H. Silva
Some bird families are more widespread than others both in geography and in habitat use (high-incidence fami- lies). The number of Mexican species in a bird family was found to be strongly correlated with the number of communi- ties that possess representatives of that family. This effect did not result from a higher probability of larger families hav- ing more widespread species or having species with broader diets or habitat preferences, nor from body size, abundance or clutch size, other factors which tend to correlate with the incidence of species. Instead, number of species per se (a trait of families) strongly influenced family incidence and thereby community composition. Therefore, community composition is influenced not only by ecological assembly rules at the species level, but also by the result of macroevolutionary proc- esses above the species level. This pattern may be related to species-area curves and provides an opportunity for coevolu- tion to occur even in situations in which species-specific coadaptation is not possible. This pattern increases the predict- ability of species composition of communities.
{"title":"Is the Taxonomic Composition of Landbird Communities in Mexico Predictable","authors":"H. Silva","doi":"10.2174/1874453200902010024","DOIUrl":"https://doi.org/10.2174/1874453200902010024","url":null,"abstract":"Some bird families are more widespread than others both in geography and in habitat use (high-incidence fami- lies). The number of Mexican species in a bird family was found to be strongly correlated with the number of communi- ties that possess representatives of that family. This effect did not result from a higher probability of larger families hav- ing more widespread species or having species with broader diets or habitat preferences, nor from body size, abundance or clutch size, other factors which tend to correlate with the incidence of species. Instead, number of species per se (a trait of families) strongly influenced family incidence and thereby community composition. Therefore, community composition is influenced not only by ecological assembly rules at the species level, but also by the result of macroevolutionary proc- esses above the species level. This pattern may be related to species-area curves and provides an opportunity for coevolu- tion to occur even in situations in which species-specific coadaptation is not possible. This pattern increases the predict- ability of species composition of communities.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"20 1","pages":"24-28"},"PeriodicalIF":0.0,"publicationDate":"2009-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-05-07DOI: 10.2174/1874453200902010017
E. H. Paxton
Plumage coloration in birds serve multiple purposes, including species recognition, sexual selection cues, and camouflage. Differences in plumage coloration can be used to infer evolutionary relationships, identify distinct taxonomic units, and characterize geographic variation. With the advent of electronic devices to quantify plumage coloration quickly and reliably, taxonomic or geographic differences can be exploited for ecological studies. To evaluate the utility of plum- age coloration for taxonomic and ecological studies, I review the basis of plumage coloration and sources of variation. I then review how different studies have used plumage coloration to better understand taxonomic relationships and provide insights into ecological problems.
{"title":"The Utility of Plumage Coloration for Taxonomic and Ecological Studies","authors":"E. H. Paxton","doi":"10.2174/1874453200902010017","DOIUrl":"https://doi.org/10.2174/1874453200902010017","url":null,"abstract":"Plumage coloration in birds serve multiple purposes, including species recognition, sexual selection cues, and camouflage. Differences in plumage coloration can be used to infer evolutionary relationships, identify distinct taxonomic units, and characterize geographic variation. With the advent of electronic devices to quantify plumage coloration quickly and reliably, taxonomic or geographic differences can be exploited for ecological studies. To evaluate the utility of plum- age coloration for taxonomic and ecological studies, I review the basis of plumage coloration and sources of variation. I then review how different studies have used plumage coloration to better understand taxonomic relationships and provide insights into ecological problems.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"67 1","pages":"17-23"},"PeriodicalIF":0.0,"publicationDate":"2009-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-04-24DOI: 10.2174/1874453200902010007
G. Kaplan, Gayle Johnson, A. Koboroff, L. Rogers
Mobbing calls are produced by many avian species as part of a defence strategy against predators. However, as most studies have described small prey species, little is known of mobbing by species large enough to inflict harm on the predator when working cooperatively. We investigated the mobbing calls of the Australian magpie (Gymnorhina tibicen tibicen), a large, territorial songbird known to be exceptionally vigilant and to attack predators. We were particularly interested in this species because it has a very large vocal repertoire. Magpie groups (N=45) in semi-rural and rural locali- ties were presented with taxidermic specimens of three predators, two species of eagle and a monitor lizard, the latter known to be a risk to their eggs and nestlings. We identified five distinct types of alarm calls, one of which (a complex, tonal call of more than two syllables) was elicited almost exclusively by the eagles in environments where they are known to be a threat to magpies. This alarm call usually preceded intense swooping attacks of the eagle models and often contin- ued during the attacks. A harsh and noisy call of one syllable was the most frequently produced call and appeared to indicate level of arousal. The lizard did not elicit the multi-syllable call or any swooping attacks but it did elicit the harsh call. Some other call types showed less stimulus specificity although a two-syllable call was elicited more commonly by the eagles than lizard. Hence, this species has an acoustically complex, multi-syllable alarm call to signal the presence of an aerial predator in contexts of genuine threat, and this call is markedly different from the harsh single-syllable call, which indicates arousal level and is used most frequently when mobbing a monitor lizard.
{"title":"Alarm Calls of the Australian Magpie ('Gymnorhina tibicen'): Predators Elicit Complex Vocal Responses and Mobbing Behaviour","authors":"G. Kaplan, Gayle Johnson, A. Koboroff, L. Rogers","doi":"10.2174/1874453200902010007","DOIUrl":"https://doi.org/10.2174/1874453200902010007","url":null,"abstract":"Mobbing calls are produced by many avian species as part of a defence strategy against predators. However, as most studies have described small prey species, little is known of mobbing by species large enough to inflict harm on the predator when working cooperatively. We investigated the mobbing calls of the Australian magpie (Gymnorhina tibicen tibicen), a large, territorial songbird known to be exceptionally vigilant and to attack predators. We were particularly interested in this species because it has a very large vocal repertoire. Magpie groups (N=45) in semi-rural and rural locali- ties were presented with taxidermic specimens of three predators, two species of eagle and a monitor lizard, the latter known to be a risk to their eggs and nestlings. We identified five distinct types of alarm calls, one of which (a complex, tonal call of more than two syllables) was elicited almost exclusively by the eagles in environments where they are known to be a threat to magpies. This alarm call usually preceded intense swooping attacks of the eagle models and often contin- ued during the attacks. A harsh and noisy call of one syllable was the most frequently produced call and appeared to indicate level of arousal. The lizard did not elicit the multi-syllable call or any swooping attacks but it did elicit the harsh call. Some other call types showed less stimulus specificity although a two-syllable call was elicited more commonly by the eagles than lizard. Hence, this species has an acoustically complex, multi-syllable alarm call to signal the presence of an aerial predator in contexts of genuine threat, and this call is markedly different from the harsh single-syllable call, which indicates arousal level and is used most frequently when mobbing a monitor lizard.","PeriodicalId":39058,"journal":{"name":"Open Ornithology Journal","volume":"2 1","pages":"7-16"},"PeriodicalIF":0.0,"publicationDate":"2009-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68077305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-04-01DOI: 10.2174/1874453200902010001
James L. Rebholz, W. Robinson, M. Pope
Nesting success of greater sage-grouse (Centrocercus urophasianus) influences annual reproductive success and population dynamics. To describe nesting habitat and measure the effects of vegetation characteristics on nesting out- comes, we sampled 87 sage-grouse nests during 2004 and 2005 in the Montana Mountains of northwestern Nevada. Within a 78.5-m 2 circular plot surrounding each nest, we quantified sagebrush canopy cover and grass cover. We used Akaike's Information Criterion to rank competing models describing potential relationships between vegetation character- istics at and surrounding sage-grouse nests and to determine those characteristics associated with nest success. Nest initia- tion rate was high (90.0%) and apparent nest success was 40.2%. We used a Mayfield estimation to determine a probabil- ity of nest success (hatch >1 chick) of 36%. Grass cover within a 3-m 2 area centered on the nest had a positive effect on nest success (odds ratio: 1.03, 95% CI: 1.005 - 1.059). We also found weak support for a positive effect on nest success of sagebrush cover at the nest (odds ratio: 1.02, 95% CI: 0.993 - 1.043). Our results are similar to previous findings and con- firm the importance of sagebrush cover and herbaceous understory for nesting. To manage sagebrush communities for successful nesting by greater sage-grouse, we recommend providing sufficient grass and sagebrush cover.
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