Name: visually sexing loggerhead shrike (lanius ludovicianus) using plumage coloration and pattern
Uploaded: 2020-03-08T12:30:00
Description: Watch this Scientific Journal Video about Visually Sexing Loggerhead Shrike Lanius Ludovicianus Using Plumage Coloration and Pattern at JoVE.com

Funding for fieldwork during which our methodologies were developed was provided by Environment Canada&#39;s Canadian Wildlife Service, Environment Canada&#39;s Strategic Technologies Application of Genomics in the Environment Research Fund, the Endangered Species Recovery Fund, the Interdepartmental Recovery Fund, the Natural Sciences and Engineering Research Council and the Ontario Ministry of Training, Colleges and Universities (scholarships to A.A.C.), Queen&#39;s University (Duncan and Urlla Carmichael Fellowship to A.A.C.) and Wildlife Preservation Canada. We wish to thank the Editor and four anonymous reviewers for their comments, which greatly improved this manuscript. Thanks to Wildlife Preservation Canada staff and the members of the North American Loggerhead Shrike Working Group for discussions that assisted in development of this methodology. We extend our thanks to all the Citizen Scientists and staff at African Lion Safari, Cambridge, Ontario, for their assistance in completing the survey. We especially thank Erin Sills, Marketing and PR Coordinator, African Lion Safari, for her assistance in producing the on-line survey and summarizing results.

The research protocol presented herein complies with African Lion Safari&#39;s Animal Care Committee guidelines.
1. Sexing Loggerhead Shrikes by Color and Patern of the Sixth Primary Wing Feather
NOTE: Shrikes can be sexed in hand based on the coloration and pattern in the sixth primary wing feather (P6). In brief, the technique requires the observer to visually extrapoloate a line along the lower edge of the primary wing coverts, and then to assess how far the brown ...

Herein, we describe a simple and efficient method whereby loggerhead shrike can be sexed based only on visual cues, and provide an assessment of the method&#39;s accuracy. Our simple method is easily and quickly undertaken, with results indicating a high accuracy rate that increases with a small amount of training. Our results support those of previous work13 that indicated the method originally developed for use in northern shrike12 had utility for sexing adult loggerhead ...

The loggerhead shrike (Lanius ludovicianus) is a North American passerine with a broad geographical range encompassing most of North America and a variety of habitats that can generally be described as grassland1. It is one of only two species of shrikes (Order Passeriformes) that occur in North America. Shrikes are best known for the unique raptor-like bill, which allows them to take vertebrate prey, and their unique behavior of impaling food items on thorns or other sharp objects. The loggerhead shrike is the only species of &#39;true shrike&#39; (Family Laniidae) endemic to the continent. Shrikes breeding above 40&#176;N are generally obligate migrants1,2,3, with wintering grounds almost entirely encompassed within that of non-migratory conspecifics1,4.
North American Breeding Bird Survey data5 for loggerhead shrike indicate a significant (3.18% yr-1) range-wide population decline. The loggerhead shrike is one of Partners in Flight&#39;s 24 &#34;Common Birds in Steep Decline&#34;-i.e., those that have lost more than 50% of their populations over the past 40 years, but which lack other elevated vulnerability factors that would warrant higher &#34;Watch List&#34; status6. Habitat loss due to succession and human development likely contributed to the initial declines4,7, but continued population declines are outpacing habitat loss in the breeding season, suggesting other limiting factors, in particular in areas where the species is an obligate migrant4,8. Results of a population viability analysis conducted for the critically endangered population of loggerhead shrike in Ontario suggests that over-wintering success of birds in their first year of life is a driver of the population trends9,10. Results further indicate that the conservation breeding effort, which is augmenting the wild population, has kept the species from extirpation in this area9,10.
Understanding sex differences is an important component of both ecological and evolutionary hypotheses. The plumage of loggerhead shrikes (Laniusludovicianus) is sexually monochromatic and therefore individuals cannot reliably be sexed in the hand. However, based on a method applicable to the northern shrike (Lanius excubitor)11,12, it has been shown to be possible to sex at least some populations of adult loggerhead shrikes using the coloration pattern in the sixth primary wing feather13. We have revised this methodology13 to include consideration of a second variable, specifically the extent of pigmentation in the rachis of the sixth primary, which allows reliable identification of sex in the majority of individuals in eastern populations, and tested its application (previously only applied to adult birds) to fledged young of the year. The method requires no specialized equipment or costly lab assays, and no measurements are required that would be subject to observer bias. Based on our results, the method is easily learned and, once mastered, highly accurate. Here, we present detailed instructions on how to sex shrike in the hand using our method and discuss the wider implications of including sex assessment in future research and conservation efforts for this unique and enigmatic species of conservation concern.

visually sexing loggerhead shrike (lanius ludovicianus) using plumage coloration and pattern

The loggerhead shrike is a small sexually monomorphic passerine bird using grassland habitats across North America. Based on Breeding Bird Survey data, the species has undergone a drastic decline since the mid-1960s. The cause of decline is unknown, and research is actively underway to address this knowledge gap. These efforts are hindered by an inability to sex the species in hand, which to date was only possible using molecular markers. Here, we present a protocol to sex loggerhead shrikes by visually analyzing the coloration and pattern in the sixth primary feather. The application of the method will facilitate our ability to identify threats on a finer scale than has been possible to date and to address various ecological and evolutionary hypotheses. The methodology is simple and results reliable&#8211;we encourage including this method for research of both in situ and ex situ populations.

Male and female plumage is, overall, monomorphic in the loggerhead shrike. However, it has been established that sex can be discerned based on the pattern of coloration in the 6th primary in the population that occurs on mainland California13 and northern shrike12. We tested Sustaita et al.&#39;s (2014) protocol13 to determine if it was applicable to northeastern populations of loggerhead shrike and to youn...

Watch this Scientific Journal Video about Visually Sexing Loggerhead Shrike Lanius Ludovicianus Using Plumage Coloration and Pattern at JoVE.com

Visually Sexing Loggerhead Shrike Lanius Ludovicianus Using Plumage Coloration and Pattern

We present a protocol to characterize the sex of loggerhead shrike visually based on the coloration and pattern of the sixth primary wing feather.

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern

The loggerhead shrike is a small sexually monomorphic passerine bird using grassland habitats across North America. Based on Breeding Bird Survey data, ...

Loggerhead shrike has lost more than 50%of the population across North America over the past 40 years. The ability to determine sex in loggerhead shrike has given us another tool to help understand what is causing the decline and how conservation breeding can best help offset the threats. The plumage of loggerhead shrike is sexually monomorphic so birds can not be reliably sexed in hand, using physical characteristics as in the case for many other species.DNA sexing is possible but is expensive, time delayed and requires special equipment. Our simple method is easy and quickly undertaken, with results indicating a high accuracy rate, that increases with a small amount of training. Shrike's can be sexed, in hand, by examining the sixth primary wing feather.However, the pattern varies amongst individuals. The most difficult part of our method is deciding how far the brown in the rachis extends through the white and only going on to additional steps if the sex cannot be determined based on this characteristic alone. We suggest that anyone who hasn't used this method before, review the video and become familiar with the characteristics they are looking at, as well as the order in which to assess them.Feel free to contact us and we can provide sample photos used in our citizen science survey. Begin by firmly holding the bird using the banders grip and carefully extending one wing to allow the sixth primary feather to be viewed, making sure to not overextend the wing. Locate the P6 feather by counting forward from the first primary.Assess the brown in the rachis and determine if it extends at least halfway through the white and touches the distal end of the primary covert feathers. If it does, the bird is female. If unsure of the sex, based on the color of the rachis, assess the symmetry of the brown to white transition on each side of the shaft.If the brown meets at the same spot on either side of the shaft, the bird is male. If the line meets asymmetrically at the shaft, creating a step or notch, the bird is a female. If there is still uncertainty, examine the angle of the transition between the brown and the white coloration.If the brown has a steep angle where it meets the white, forming an upside down V, the bird is a female. If the pattern looks more like an M, the bird is male. This sexing protocol was tested on 120 participants, who read a brief instruction on how to sex using feather patterns and then attempted to sex a series of 26 shrikes based on a photograph.Most participants ranked themselves as having little or no experience with birds. The participants averaged a 77%correct assessment for both females and males. Ten volunteers received in person training on this method and attempted to sex the same series of 26 photos which they had not seen before.The individuals trained one on one, correctly assessed 12 out of 13 photos of females and 11 out of 13 photos of males. When attempting this method, the most critical step is determining how far the brown in the rachis extends through the white, only if there is question about whether or not the brown touches the primary coverts, should the observer continue on to assess other characteristics. Out method of sexing shrike in hand, can be done when handling wild shrike's during banding, and included with other data collection like age and wing cord length.For captive birds, sexing can coincide with the need to handle birds for vaccination, banding or other routine management. To date, more than 1000 young birds have been released into the wilds of Ontario. A rapid and inexpensive method for sexing young birds makes it possible to quantify how many birds of each sex are released and if sex biased mortality is occurring.

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