T. Ryan, Stacey M. Vigallon, Ross Griswold, Lucien Plauzoles, Cheryl Egger, Susan Sheakley, L. Nguyen, Robert Schallmann
From 2004 to 2021 we monitored the Western Snowy Plover (Charadrius nivosus nivosus) in coastal Los Angeles and Orange counties, California. Following an absence of 68 years, it returned to nest in 2017. Since then, the plovers have nested at three locations in Los Angeles County and four in Orange County, where numbers of nests at Anaheim Bay, Bolsa Chica State Beach, and Huntington State Beach increased. Protective beach management and nest enclosures presumably contributed to the increase of nests and hatching success at these sites. However, the number of nonbreeding Snowy Plovers in coastal Los Angeles County has declined, most steeply at Zuma Beach. At nonbreeding roosts in Orange County numbers at Balboa Beach and San Onofre State Beach declined, but countywide numbers were stable. All sites at which plovers roost experience human-related disturbance, which may include vehicles driving through them regularly, beach grooming that removes wrack and foraging resources, dogs chasing and flushing roosting plovers, and nearby large recreational events and summer camps as nonbreeding plovers return in July. Most sites lack consistent protective measures. Plover mortality has resulted from vehicle strikes and dogs. We recommend management that includes the establishment of special protection zones, restrictions on sand grooming, wrack removal, and vehicle traffic, and installation of protective enclosures around roost sites.
{"title":"Status of the Western Snowy Plover in Coastal Los Angeles and Orange Counties, California","authors":"T. Ryan, Stacey M. Vigallon, Ross Griswold, Lucien Plauzoles, Cheryl Egger, Susan Sheakley, L. Nguyen, Robert Schallmann","doi":"10.21199/wb54.1.4","DOIUrl":"https://doi.org/10.21199/wb54.1.4","url":null,"abstract":"From 2004 to 2021 we monitored the Western Snowy Plover (Charadrius nivosus nivosus) in coastal Los Angeles and Orange counties, California. Following an absence of 68 years, it returned to nest in 2017. Since then, the plovers have nested at three locations in Los Angeles County and four in Orange County, where numbers of nests at Anaheim Bay, Bolsa Chica State Beach, and Huntington State Beach increased. Protective beach management and nest enclosures presumably contributed to the increase of nests and hatching success at these sites. However, the number of nonbreeding Snowy Plovers in coastal Los Angeles County has declined, most steeply at Zuma Beach. At nonbreeding roosts in Orange County numbers at Balboa Beach and San Onofre State Beach declined, but countywide numbers were stable. All sites at which plovers roost experience human-related disturbance, which may include vehicles driving through them regularly, beach grooming that removes wrack and foraging resources, dogs chasing and flushing roosting plovers, and nearby large recreational events and summer camps as nonbreeding plovers return in July. Most sites lack consistent protective measures. Plover mortality has resulted from vehicle strikes and dogs. We recommend management that includes the establishment of special protection zones, restrictions on sand grooming, wrack removal, and vehicle traffic, and installation of protective enclosures around roost sites.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88261872","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}
G. Ruiz-Campos, Gonzalo De Leon-Giron, Tonatiuh Gaona-Melo, G. Marrón, P. Unitt, L. Hargrove
A specimen of the Least Grebe (Tachybaptus dominicus bangsi) from San Francisco de la Sierra, Baja Calfornia Sur, Mexico, collected 6 April 2022, was 36 km north of the oasis of San Ignacio, where the species breeds and site of the previous northernmost records on the peninsula. The bird’s occurrence on a small isolated pond yet coming into breeding condition highlight the species’ opportunism, possibly critical to its survival on the arid Baja California peninsula where freshwater oases suitable for the Least Grebe are few.
2022年4月6日，在墨西哥下加利福尼亚州南部San Francisco de la Sierra采集到的最小格里贝(Tachybaptus dominicus bangsi)标本位于圣伊格纳西奥绿洲以北36公里处，该物种在那里繁殖，也是该半岛之前最北端记录的地点。这只鸟出现在一个小的孤立池塘里，但却进入了繁殖条件，这凸显了该物种的机会主义，这可能对它在干旱的下加利福尼亚半岛上的生存至关重要，因为那里适合最小Grebe的淡水绿洲很少。
{"title":"The Northernmost Record of the Least Grebe (Tachybaptus dominicus bangsi) in Baja California","authors":"G. Ruiz-Campos, Gonzalo De Leon-Giron, Tonatiuh Gaona-Melo, G. Marrón, P. Unitt, L. Hargrove","doi":"10.21199/wb54.1.8","DOIUrl":"https://doi.org/10.21199/wb54.1.8","url":null,"abstract":"A specimen of the Least Grebe (Tachybaptus dominicus bangsi) from San Francisco de la Sierra, Baja Calfornia Sur, Mexico, collected 6 April 2022, was 36 km north of the oasis of San Ignacio, where the species breeds and site of the previous northernmost records on the peninsula. The bird’s occurrence on a small isolated pond yet coming into breeding condition highlight the species’ opportunism, possibly critical to its survival on the arid Baja California peninsula where freshwater oases suitable for the Least Grebe are few.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86287891","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}
The Swainson’s Hawk (Buteo swainsoni) has a long history of breeding in California, but a severe decline in the statewide breeding population was identified in 1979, when in all of southern California only two pairs were found, one in the Antelope Valley of the western Mojave Desert. That area was little studied until we began banding Swainson’s Hawks there in 1997. Over 20 breeding seasons between 1979 and 2022, we documented in the Antelope Valley 124 attempts to nest, in which the mean clutch and brood sizes were 2.49 and 2.37, respectively. From 2004 through 2006, we observed two to four breeding pairs annually; from 2009 through 2022, three to 14 breeding pairs. The rate of success of the 91 nests revisited to determine if any young fledged was 64%. Nest trees consisted of 81.5% non-native species, 13.7% native species, including Joshua trees (Yucca brevifolia), and 4.8% unidentified deciduous trees. Between 1997 and 2022, in 50 nests, we recorded 170 vertebrate prey items, of which 90 were gophers (Thomomys bottae). Though the Antelope Valley population has grown since 1980, its nesting and foraging habitat now face multiple threats. To conserve occupied nesting territories, we recommend creation of nesting and foraging habitat reserves that include both native desert and cultivated alfalfa close to existing conserved land.
{"title":"Swainson’s Hawk Nesting Population in the Antelope Valley of the Western Mojave Desert, California","authors":"P. Bloom, Rainey G. Barton, Michael J. Kuehn","doi":"10.21199/wb54.1.3","DOIUrl":"https://doi.org/10.21199/wb54.1.3","url":null,"abstract":"The Swainson’s Hawk (Buteo swainsoni) has a long history of breeding in California, but a severe decline in the statewide breeding population was identified in 1979, when in all of southern California only two pairs were found, one in the Antelope Valley of the western Mojave Desert. That area was little studied until we began banding Swainson’s Hawks there in 1997. Over 20 breeding seasons between 1979 and 2022, we documented in the Antelope Valley 124 attempts to nest, in which the mean clutch and brood sizes were 2.49 and 2.37, respectively. From 2004 through 2006, we observed two to four breeding pairs annually; from 2009 through 2022, three to 14 breeding pairs. The rate of success of the 91 nests revisited to determine if any young fledged was 64%. Nest trees consisted of 81.5% non-native species, 13.7% native species, including Joshua trees (Yucca brevifolia), and 4.8% unidentified deciduous trees. Between 1997 and 2022, in 50 nests, we recorded 170 vertebrate prey items, of which 90 were gophers (Thomomys bottae). Though the Antelope Valley population has grown since 1980, its nesting and foraging habitat now face multiple threats. To conserve occupied nesting territories, we recommend creation of nesting and foraging habitat reserves that include both native desert and cultivated alfalfa close to existing conserved land.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74105138","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}
The Pallas’s Gull Ichthyaetus ichthyaetus is a fish-eating predator listed in the category of recovering species of the Red Book of the Russian Federation. The purpose of the research was to study the state of the Pallasʹs Gull in the fairway (navigable zone) of the Volga–Kama reservoirs, in Russia and to assess their role in the current distribution of the species. In the summer and autumn of 2020–2022, at 11 reservoirs of the Volga and Kama rivers, counts of Pallasʹs Gulls were carried out from the bow deck of the R/V Akademik Topchiev. The transect length was 4633.5 km; the duration of observations was 364.3 h. A comprehensive bird count was applied in the direction of the vessel’s movement on transects with a fixed counting strip width of 200 m (100 m in each direction from the bow of the vessel). Birds were usually fixed on 30-min transects. The Pallas’s Gulls were found in 7 of the 11 reservoirs studied, and their status varied between common and very rare. The species was more abundant in the Gorky reservoir than in the Cheboksary, Kuibyshev, Saratov, and Nizhnekamsk reservoirs. The smallest abundance was recorded in the Volgograd and Rybinsk reservoirs. The Pallas’s Gull shows a steady annual presence on most reservoirs. The results indicate that in the Volga Basin, the range of Pallas’s Gull has expanded further north by more than 1000 km over the past 30 years from the species’ original areas of sustainable breeding in the North Caspian. Adult individuals of the Pallasʹs Gull (83.4% of the age composition of the population) play the main role in the dispersal. The most favorable clusters of the stable presence of the species were lake-shaped fragments of the Gorky and Kuibyshev reservoirs. On the territory of the East European Plain, the Volga–Kama reservoirs are important, if not decisive, in expanding the range of Pallas’s Gull to the north.
帕拉斯海鸥鱼鱼鱼是一种被列入俄罗斯联邦红皮书恢复物种类别的食鱼食肉动物。这项研究的目的是研究俄罗斯伏尔加-卡马水库航道(通航区)的帕拉斯海鸥的状况，并评估它们在该物种当前分布中的作用。在2020-2022年的夏季和秋季，在伏尔加河和卡马河的11个水库，从R/V Akademik Topchiev的艏甲板上进行了Pallas ' s鸥的计数。样带长度4633.5 km;观测时间为364.3 h。在距船首各方向100 m的固定计数条宽度为200 m的样条上，沿船移动方向进行综合鸟类计数。鸟类通常被固定在30分钟的横断面上。在研究的11个水库中，有7个发现了帕拉斯海鸥，它们的状况在常见和非常罕见之间变化。高尔基水库的种类比切博克萨里、古比雪夫、萨拉托夫和尼日涅卡姆斯克水库丰富。伏尔加格勒和雷宾斯克水库的丰度最低。帕拉斯海鸥每年都在大多数水库出现。结果表明，在伏尔加盆地，在过去的30年里，帕拉斯海鸥的活动范围从该物种在北里海的原始可持续繁殖区域向北扩展了1000多公里。成年个体(占种群年龄组成的83.4%)在扩散过程中起主要作用。高尔基和古比雪夫水库的湖状碎片是该物种稳定存在的最有利的集群。在东欧平原的领土上，伏尔加-卡马水库是重要的，如果不是决定性的，在扩大帕拉斯海鸥的范围向北。
{"title":"Status of the Pallas’s Gull Ichthyaetus ichthyaetus during Summer/Autumn in the Fairway Volga–Kama Reservoirs (East European Plain) in Russia","authors":"S. Golubev","doi":"10.3390/birds4010004","DOIUrl":"https://doi.org/10.3390/birds4010004","url":null,"abstract":"The Pallas’s Gull Ichthyaetus ichthyaetus is a fish-eating predator listed in the category of recovering species of the Red Book of the Russian Federation. The purpose of the research was to study the state of the Pallasʹs Gull in the fairway (navigable zone) of the Volga–Kama reservoirs, in Russia and to assess their role in the current distribution of the species. In the summer and autumn of 2020–2022, at 11 reservoirs of the Volga and Kama rivers, counts of Pallasʹs Gulls were carried out from the bow deck of the R/V Akademik Topchiev. The transect length was 4633.5 km; the duration of observations was 364.3 h. A comprehensive bird count was applied in the direction of the vessel’s movement on transects with a fixed counting strip width of 200 m (100 m in each direction from the bow of the vessel). Birds were usually fixed on 30-min transects. The Pallas’s Gulls were found in 7 of the 11 reservoirs studied, and their status varied between common and very rare. The species was more abundant in the Gorky reservoir than in the Cheboksary, Kuibyshev, Saratov, and Nizhnekamsk reservoirs. The smallest abundance was recorded in the Volgograd and Rybinsk reservoirs. The Pallas’s Gull shows a steady annual presence on most reservoirs. The results indicate that in the Volga Basin, the range of Pallas’s Gull has expanded further north by more than 1000 km over the past 30 years from the species’ original areas of sustainable breeding in the North Caspian. Adult individuals of the Pallasʹs Gull (83.4% of the age composition of the population) play the main role in the dispersal. The most favorable clusters of the stable presence of the species were lake-shaped fragments of the Gorky and Kuibyshev reservoirs. On the territory of the East European Plain, the Volga–Kama reservoirs are important, if not decisive, in expanding the range of Pallas’s Gull to the north.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82361025","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}
About four million photographic records of Brazilian birds are deposited in the WikiAves database. The objective of this study was to examine the spatiotemporal distribution of photographic records available in this database. Searches were performed in the database in 2022. Record numbers produced by citizens were obtained by selecting states and municipalities in different periods. The annual record production in Brazil has increased substantially since 2009, reaching about 400,000 records per year in 2020–2021. Most records were obtained in the Sudeste and Sul geopolitical regions. Seasonal variations in record production in the Cerrado and the Atlantic Forest are comparable, with more records obtained in July–October. In Amazonia, a more substantial decrease in record production occurred between November and April. The monthly record production was more uniform in the Caatinga. When municipalities were compared, similar seasonal variation in record production was observed for four ecosystems (Amazonia, Atlantic Forest, Cerrado and Pampa). However, substantial differences were observed for municipalities in the Pantanal and the Caatinga. The results indicate that high human density, high individual income and the breeding season of birds are potential factors leading to high record production. On the other hand, heavy rainfall, flooding, remoteness and environmental harshness are pointed out as factors potentially leading to relatively fewer records. Further, this article discusses the implications of record availability for ornithological studies that use photographic records deposited in the WikiAves database.
{"title":"Spatiotemporal Distribution of Photographic Records of Brazilian Birds Available in the WikiAves Citizen Science Database","authors":"D. P. Tubelis","doi":"10.3390/birds4010003","DOIUrl":"https://doi.org/10.3390/birds4010003","url":null,"abstract":"About four million photographic records of Brazilian birds are deposited in the WikiAves database. The objective of this study was to examine the spatiotemporal distribution of photographic records available in this database. Searches were performed in the database in 2022. Record numbers produced by citizens were obtained by selecting states and municipalities in different periods. The annual record production in Brazil has increased substantially since 2009, reaching about 400,000 records per year in 2020–2021. Most records were obtained in the Sudeste and Sul geopolitical regions. Seasonal variations in record production in the Cerrado and the Atlantic Forest are comparable, with more records obtained in July–October. In Amazonia, a more substantial decrease in record production occurred between November and April. The monthly record production was more uniform in the Caatinga. When municipalities were compared, similar seasonal variation in record production was observed for four ecosystems (Amazonia, Atlantic Forest, Cerrado and Pampa). However, substantial differences were observed for municipalities in the Pantanal and the Caatinga. The results indicate that high human density, high individual income and the breeding season of birds are potential factors leading to high record production. On the other hand, heavy rainfall, flooding, remoteness and environmental harshness are pointed out as factors potentially leading to relatively fewer records. Further, this article discusses the implications of record availability for ornithological studies that use photographic records deposited in the WikiAves database.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83529296","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}
Urbanization influences the food availability and quality for birds in many ways. Although a great amount of food for birds is provided incidentally or intentionally in urban areas, the quantity of insect-based food can be reduced in cities. We studied the role of one artificial food source, insects smashed on the front panels of cars, in Finland, and more specifically in the city of Rovaniemi, by conducting questionnaire research, searching for data from databases and performing a field study. Our results indicated that a total of seven bird species have been detected using insects on the front panels of cars in Finland. However, this behavior is not yet common since about 60% of responders to the questionnaire stated that this behavior is currently either rare or very rare. Most of the observations identified House Sparrows, followed by the White Wagtail or the Eurasian Jackdaw. Only a few observations identified the Eurasian Tree Sparrow, the Hooded Crow, the Great Tit and the Eurasian Magpie. The phenomenon was distributed quite widely across Finland, except in the case of the Eurasian Jackdaws, for which observations were restricted only to the southern part of the country. The first observation was made about the House Sparrow in 1971, followed by the White Wagtail (1975), Hooded Crow (1997), Eurasian Jackdaw (2006), Eurasian Tree Sparrow (2011), Eurasian Magpie (2019) and Great Tit (2022). The species using this food source are mainly sedentary urban exploiters, such as corvids and sparrows, that have been previously reported to have several different types of innovative behaviors. Most of the observations were conducted in urban parking sites of hypermarkets, and no observations were made in residential areas. Most of the foraging observations were made during the end phase of the breeding season, partly supporting the extra need for high-quality insect-based food for nestlings and fledglings. Our observations indicate that this behavior is not yet common and widespread among species.
{"title":"Urban Birds Using Insects on Front Panels of Cars","authors":"J. Jokimäki, Marja‐Liisa Kaisanlahti‐Jokimäki","doi":"10.3390/birds4010002","DOIUrl":"https://doi.org/10.3390/birds4010002","url":null,"abstract":"Urbanization influences the food availability and quality for birds in many ways. Although a great amount of food for birds is provided incidentally or intentionally in urban areas, the quantity of insect-based food can be reduced in cities. We studied the role of one artificial food source, insects smashed on the front panels of cars, in Finland, and more specifically in the city of Rovaniemi, by conducting questionnaire research, searching for data from databases and performing a field study. Our results indicated that a total of seven bird species have been detected using insects on the front panels of cars in Finland. However, this behavior is not yet common since about 60% of responders to the questionnaire stated that this behavior is currently either rare or very rare. Most of the observations identified House Sparrows, followed by the White Wagtail or the Eurasian Jackdaw. Only a few observations identified the Eurasian Tree Sparrow, the Hooded Crow, the Great Tit and the Eurasian Magpie. The phenomenon was distributed quite widely across Finland, except in the case of the Eurasian Jackdaws, for which observations were restricted only to the southern part of the country. The first observation was made about the House Sparrow in 1971, followed by the White Wagtail (1975), Hooded Crow (1997), Eurasian Jackdaw (2006), Eurasian Tree Sparrow (2011), Eurasian Magpie (2019) and Great Tit (2022). The species using this food source are mainly sedentary urban exploiters, such as corvids and sparrows, that have been previously reported to have several different types of innovative behaviors. Most of the observations were conducted in urban parking sites of hypermarkets, and no observations were made in residential areas. Most of the foraging observations were made during the end phase of the breeding season, partly supporting the extra need for high-quality insect-based food for nestlings and fledglings. Our observations indicate that this behavior is not yet common and widespread among species.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79860648","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}
Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation.
{"title":"When to Return to Normal? Temporal Dynamics of Vigilance in Four Situations","authors":"C. Mettke-Hofmann","doi":"10.3390/birds4010001","DOIUrl":"https://doi.org/10.3390/birds4010001","url":null,"abstract":"Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82208715","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}
The design of bird diverters should be based upon the perception of birds, not the perception of humans, but until now it is human vision that has guided diverter design. Aspects of bird vision pertinent to diverter design are reviewed. These are applied in an example that uses Canada Geese Branta canadensis as a putative worst-case example of a collision-prone species. The proposed design uses an achromatic checkerboard pattern of high contrast whose elements match the low spatial resolution of these birds when they are active under twilight light levels. The detectability of the device will be increased by movement, and this is best achieved with a device that rotates on its own axis driven by the wind. The recommended spacing of diverters along a power line is based upon the maximum width of the bird’s binocular field and the linear distance that it subtends at a distance sufficient to allow a bird to alter its flight path before possible impact. Given the worst-case nature of this example, other bird species should detect and avoid such a device. The basic design can be modified for use with specific target species if sufficient is known about their vision. Field trials of devices based on these design criteria are now required.
{"title":"Vision-Based Design and Deployment Criteria for Power Line Bird Diverters","authors":"G. Martin","doi":"10.3390/birds3040028","DOIUrl":"https://doi.org/10.3390/birds3040028","url":null,"abstract":"The design of bird diverters should be based upon the perception of birds, not the perception of humans, but until now it is human vision that has guided diverter design. Aspects of bird vision pertinent to diverter design are reviewed. These are applied in an example that uses Canada Geese Branta canadensis as a putative worst-case example of a collision-prone species. The proposed design uses an achromatic checkerboard pattern of high contrast whose elements match the low spatial resolution of these birds when they are active under twilight light levels. The detectability of the device will be increased by movement, and this is best achieved with a device that rotates on its own axis driven by the wind. The recommended spacing of diverters along a power line is based upon the maximum width of the bird’s binocular field and the linear distance that it subtends at a distance sufficient to allow a bird to alter its flight path before possible impact. Given the worst-case nature of this example, other bird species should detect and avoid such a device. The basic design can be modified for use with specific target species if sufficient is known about their vision. Field trials of devices based on these design criteria are now required.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73653634","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}
S. González, F. Morinha, D. Villanúa, Lander Goñi, G. Blanco
The Eurasian tree sparrow (Passer montanus) is a monomorphic passerine, for which it is impossible to differentiate between males and females based on external characteristics. Being a species frequently captured for ringing, having a reliable method to determine sex from conventional biometric measurements would facilitate its study and be very useful for the correct management and conservation of this declining species. In the present study, we used biometric measurements recorded in 66 individuals captured with mist nets in communal roosts in northern Spain during the winter and sexed them using molecular techniques. We conducted a discriminant function analysis (DFA) to derive equations that allowed us to determine the sex of the specimens from some of the measurements recorded in the field. Significant differences were found between males and females in wing length, third primary length, badge width and height and body weight. The DFA provided two functions that correctly classified the sex of 94.7% of the individuals using wing length and badge width, and 98.2% if weight was added to the analysis. Our results allow sexing from measurements that can be easily recorded in the field with the tools commonly used in banding sessions and without the need for additional training. Considerations of Bergmann’s and Allen’s rules on body size and the use of DFA in different populations are discussed.
{"title":"Discriminant Criteria for Field Sexing in the Eurasian Tree Sparrow by Combining Body Size and Plumage Features","authors":"S. González, F. Morinha, D. Villanúa, Lander Goñi, G. Blanco","doi":"10.3390/birds3040027","DOIUrl":"https://doi.org/10.3390/birds3040027","url":null,"abstract":"The Eurasian tree sparrow (Passer montanus) is a monomorphic passerine, for which it is impossible to differentiate between males and females based on external characteristics. Being a species frequently captured for ringing, having a reliable method to determine sex from conventional biometric measurements would facilitate its study and be very useful for the correct management and conservation of this declining species. In the present study, we used biometric measurements recorded in 66 individuals captured with mist nets in communal roosts in northern Spain during the winter and sexed them using molecular techniques. We conducted a discriminant function analysis (DFA) to derive equations that allowed us to determine the sex of the specimens from some of the measurements recorded in the field. Significant differences were found between males and females in wing length, third primary length, badge width and height and body weight. The DFA provided two functions that correctly classified the sex of 94.7% of the individuals using wing length and badge width, and 98.2% if weight was added to the analysis. Our results allow sexing from measurements that can be easily recorded in the field with the tools commonly used in banding sessions and without the need for additional training. Considerations of Bergmann’s and Allen’s rules on body size and the use of DFA in different populations are discussed.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89492176","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}
Flamingos (Phoenicopteriformes) are obligate colonial species that nest in large colonies, with monogamous pairs rearing a single chick following a synchronised group courtship display. Within this relatively simplistic behavioural description, deviations from these social and reproductive norms are apparent. Same sex pairings, multi-bird relationships and extra pair copulations are documented in the literature. Flamingos display highly sexually selected characteristics of plumage colour, carotenoid accumulation and diversity of display movements that underpin mate choice decisions. The brightest birds in best body condition are more successful at breeding. Therefore, documented mate guarding of female birds by male partners, is a relevant response to maximise investment in a pair bond. Limited information that describes the action of forced copulation by the male flamingo and the response of the female bird is available in the literature. This paper describes an occurrence of an attempted forced copulation by an older male Greater Flamingo to a younger female bird. Such behaviour may be an artefact of the captive environment, and limited mate choice when compared to the sizes of wild flocks, or it could be regularly apparent in the wild and therefore worthy of more scrutiny and empirical study.
{"title":"Observation of an Attempted Forced Copulation within a Captive Flock of Greater Flamingos (Phoenicopterus roseus)","authors":"P. Rose","doi":"10.3390/birds3040025","DOIUrl":"https://doi.org/10.3390/birds3040025","url":null,"abstract":"Flamingos (Phoenicopteriformes) are obligate colonial species that nest in large colonies, with monogamous pairs rearing a single chick following a synchronised group courtship display. Within this relatively simplistic behavioural description, deviations from these social and reproductive norms are apparent. Same sex pairings, multi-bird relationships and extra pair copulations are documented in the literature. Flamingos display highly sexually selected characteristics of plumage colour, carotenoid accumulation and diversity of display movements that underpin mate choice decisions. The brightest birds in best body condition are more successful at breeding. Therefore, documented mate guarding of female birds by male partners, is a relevant response to maximise investment in a pair bond. Limited information that describes the action of forced copulation by the male flamingo and the response of the female bird is available in the literature. This paper describes an occurrence of an attempted forced copulation by an older male Greater Flamingo to a younger female bird. Such behaviour may be an artefact of the captive environment, and limited mate choice when compared to the sizes of wild flocks, or it could be regularly apparent in the wild and therefore worthy of more scrutiny and empirical study.","PeriodicalId":52426,"journal":{"name":"Western Birds","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88941689","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}
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