Journal of Raptor Research最新文献

{"title":"American Kestrels Compete with European Starlings over Nest Boxes in Eastern Pennsylvania","authors":"Matthew J. Bowers, Paula M. Orozco-Valor, Rebecca A. McCabe, J. Therrien","doi":"10.3356/jrr-22-88","DOIUrl":"https://doi.org/10.3356/jrr-22-88","url":null,"abstract":"\u0000 The American Kestrel (Falco sparverius) has been steadily declining throughout most of its eastern North American range, and the cause of this decline is still relatively unknown. As a cavity nesting species, the American Kestrel often competes with other cavity nesters such as the invasive and abundant European Starling (Sturnus vulgaris) over nest boxes. The relationship between European Starling presence at nesting sites and American Kestrel occupancy and nesting success is understudied. We analyzed data from nest boxes monitored in eastern Pennsylvania, USA, from 1992 to 2021 to identify changes in occupancy of American Kestrels and competitors, and to examine the relationship between competition at nest boxes and American Kestrel nesting parameters. We found that American Kestrel occupancy decreased while European Starling occupancy increased over the study period. All other species occupying nest boxes (small mammals, passerines, owls, and snakes) showed no significant occupancy trends. On average 21% of nest boxes remained unoccupied annually, and 7% of occupied nest boxes were used by both American Kestrels and competitors in the same breeding season. The presence of these competitors had negative associations with American Kestrel occupancy, clutch size, number of fledglings produced, and overall nesting success. Specifically, the rate of nesting success decreased by 26% when European Starlings used the same nest box within the same breeding season. In recent years, nesting productivity of American Kestrels has decreased, with the average number of nestlings, fledglings, and nesting success rate all declining, while the average clutch size remained constant. Our results suggest that American Kestrel nesting parameters in eastern Pennsylvania are negatively associated with competition for nest boxes during the breeding season. The opposing trends in occupancy for the European Starling and the American Kestrel in this study area coupled with the declining productivity of American Kestrel nests raise concerns over the future of this raptor species in eastern Pennsylvania.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86789697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Approach Improves Monitoring of Wintering Red Kites in Central Europe","authors":"Marek Dostál, I. Literák, D. Horal, J. Svetlik, R. Raab, J. Hohenegger, H. Matušík","doi":"10.3356/jrr-22-97","DOIUrl":"https://doi.org/10.3356/jrr-22-97","url":null,"abstract":"\u0000 The Red Kite (Milvus milvus) is a common raptor in suitable areas of Austria, the Czech Republic, and Slovakia during the nonbreeding season. However, the exact number of birds wintering in these countries remains unknown. Through an integrated approach using satellite telemetry, direct field surveys at nocturnal roosts, and citizen science databases, we estimated the wintering population of Red Kites in this area during the winter of 2020/2021. Based on three surveys taking place at the beginning (28 November 2020), middle (9 January 2021), and end (5 February 2021) of winter, respectively, we counted 566, 558, and 536 Red Kites. The observations from online citizen science databases mostly appeared to correspond with the area of communal roost sites. Using our combined approach, the estimates of wintering Red Kites were determined as minimum numbers in the study area. A comparison of historical data (from the second half of the 20th and beginning of the 21st centuries, respectively) and our own results suggests that the wintering population of Red Kites in the study area has increased substantially. This dynamic could be caused by changes in climatic conditions, a shift of the birds' breeding range in Europe, changes in migration behavior and/or food availability, and/or conservation efforts.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77444454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution GPS Tracking of American Kestrels Reveals Breeding and Post-breeding Ranging Behavior in Northern Virginia, USA","authors":"J. Kolowski, Caylen Wolfer, Megan McDaniels, Alan Williams, J. Harris","doi":"10.3356/jrr-22-106","DOIUrl":"https://doi.org/10.3356/jrr-22-106","url":null,"abstract":"\u0000 Long-term monitoring data indicate a persistent decline in American Kestrel populations across North America. Loss or alteration of habitat have been listed as potential causal factors, but basic information on kestrel space use, including breeding home range size, is lacking. No study has provided robust estimates of the ranging behavior of breeding kestrels based on tracking data of any resolution. We fitted 19 adult female kestrels with solar-powered GPS transmitters during the incubation period in northern Virginia. High-resolution tracking began during the early nestling stage for 17 birds. We collected an average of 1710 locations per bird through the end of the breeding season (31 August), with 13 birds tracked through the fledging of their young. Autocorrelated kernel density home range estimation showed that female kestrels used breeding home ranges that were smaller (average: 0.32 km2) than most previously published range sizes. Home ranges did not vary significantly in size across breeding stages and demonstrated little overlap with the ranges of neighboring kestrels. Five females shifted their territories in the post-breeding stage (i.e., after disappearance or dispersal of fledglings) between 1.5 and 12.3 km from their nest box; they maintained these new ranges at least to the migration period. We also documented home range excursion forays (n = 128) by all 12 consistently tracked females. Mean (4.0 km) and maximum (127.7 km) foray distances were some of the largest reported among birds and mammals relative to home range size. Weekly foray rates were highest during the nestling stage, and for birds that ultimately shifted from their breeding home range. The existence of long-distance foray behavior and the use of multiple summer home ranges, both shown here for the first time for this species, has a direct impact on interpretation of kestrel nest-site and habitat selection data, and on the assessment of potential threats to this species in the breeding season.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81713146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trio of Aplomado Falcons Captures a Swallow-tailed Kite","authors":"Kennedy Borges, J. O. Coulson","doi":"10.3356/jrr-23-01","DOIUrl":"https://doi.org/10.3356/jrr-23-01","url":null,"abstract":"","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82646372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abundance and Breeding Ecology of Critically Endangered Vultures in Mole National Park, Ghana","authors":"Sandra Goded, Nathaniel N. D. Annorbah, O. Boissier, Kristen M. Rosamond, Samuel Boakye Yiadom, Zébigou Kolani, A. Mahama, N. Arcilla","doi":"10.3356/jrr-22-54","DOIUrl":"https://doi.org/10.3356/jrr-22-54","url":null,"abstract":"\u0000 Vultures are among the most threatened species in Africa, with several critically endangered species surviving mainly or only in protected areas. West African vulture declines are correlated with steep losses of natural habitat and mammalian wildlife. Major factors driving vulture extirpations include wildlife trade for traditional medicine, belief-based rituals, and bushmeat. Current data on vulture abundance and breeding ecology are crucial for conservation but lacking in many countries, including Ghana. Between 2020 and 2022, we conducted 761 km of surveys for critically endangered vultures in Mole National Park (Mole NP), a 4840 km2 protected savanna in northern Ghana. Using our count data, we estimated populations of 29–36 Hooded Vultures (Necrosyrtes monachus), 25–73 White-backed Vultures (Gyps africanus), and 3–4 White-headed Vultures (Trigonoceps occipitalis) in the southern region of Mole NP. We also documented 17 occupied vulture nests, including six Hooded Vulture nests, 10 White-backed Vulture nests, and one White-headed Vulture nest. Our findings include the first nest records for Hooded Vultures in Mole NP, the first nest description of White-backed Vultures in Ghana, and the first nest records for White-headed Vultures in Ghana, confirming the importance of Mole NP for conserving critically endangered vultures. Reducing poaching, preventing the killing of vultures for wildlife trade, and protecting vulture habitat and food resources will be paramount to the survival of critically endangered vultures in Ghana and West Africa.","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86950075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conspecific Carcass Removal from a Wind Project Study Plot by a Great Horned Owl (Bubo virginianus)","authors":"D. Bell, S. Snyder, Joseph E. Didonato, K. S. Smallwood","doi":"10.3356/JRR-21-65","DOIUrl":"https://doi.org/10.3356/JRR-21-65","url":null,"abstract":"Assessing impacts of wind farms on volant animals requires conducting fatality monitoring studies that incorporate integrated carcass detection trials to account for searcher detection probability and carcass persistence and to reduce biases in the estimated number of fatalities (Smallwood et al. 2018). These trials involve placing a wide range of volant animal carcasses that mimic the expected species composition and actual spatial and temporal patterns of fatalities deposited by the wind turbines and measuring rates of carcass detection (Smallwood et al. 2018). When combined with remote cameras, carcass placement trials can reveal the suite of local scavengers that affect carcass persistence. We report here on an incident of conspecific carcass removal by a Great Horned Owl (Bubo virginianus) documented during a study designed to assess scavenger removal rates of avian carcasses at a wind energy project (Smallwood et al. 2009, 2010). We conducted the scavenger removal study from 12 December 2006 to 28 September 2007 on a 250ha parcel of land administered by the East Bay Regional Park District in the Altamont Pass Wind Resource Area, California, USA. The study area contained 52 functional wind turbines situated in rows along ridgelines within a landscape dominated by annual grasses. Sixty-three avian carcasses representing diverse avian species and body sizes, including two Great Horned Owls, were used for this study. Carcasses were obtained fresh-dead as either road kills or from animal rehabilitation hospitals and were kept frozen until used. To avoid scavenger swamping, from one to five carcasses were placed each week at randomly chosen locations within 60-m radii of wind turbine bases throughout the facility. Infrared, motion-activated cameras (Reconyxt, Holmen, WI, USA) were attached to metal posts approximately 1 m above the ground and 1.5 m away from each carcass. When activated, the cameras were set to take five pictures in rapid succession, with a recovery phase of approximately 1 sec between firings. All scavenging trial locations were monitored with cameras for 21 d after carcass placement or until a carcass was removed by scavengers, whichever came first. In some instances, camera removals were delayed beyond 21 d due to field conditions. After cameras were removed, all trial locations with either partial carcasses or feathers continued to be monitored weekly by biologists until the end of the study. For more details on this study, see Smallwood et al. (2009). A Great Horned Owl carcass was placed on 19 December 2006 at 1500 H in front of a remote camera set-up. On 13 January 2007, at 1843 H, a Great Horned Owl was photographed landing on","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84866319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commentary: Subadult Nest Occupancy Rates and Floater-To-Breeder Ratios in Raptor Population Assessment","authors":"W. G. Hunt, P. Law","doi":"10.3356/JRR-22-87","DOIUrl":"https://doi.org/10.3356/JRR-22-87","url":null,"abstract":"Subadult (immature) raptors of a variety of species are capable of holding breeding territories and even reproducing (Newton 1979, Steenhof et al. 1983). Robust populations, however, typically contain few, if any, pair members in pre-definitive plumage, and the general explanation is that adults tend to outcompete younger individuals for territory ownership where space is limiting. Their rarity as territory-holders can therefore be a useful indicator of breeding habitat saturation, whereas their increase has been considered ‘‘early warning’’ that vital rates (survival and reproduction) are insufficient to fill territorial space (Ferrer and Donazar 1996, Ferrer et al. 2003). Territory saturation also constitutes a threshold beyond which floaters (nonterritorial adults) can be expected to accumulate. The size of such a population and the ratio of floaters to territory-holders will stabilize if vital rates remain high enough to maintain saturation, a mode of population limitation known as Moffat’s equilibrium (Hunt 1998). The equilibrium floater-tobreeder ratio is useful in broadly indexing the durability of territory saturation as well as the degree of expected feedback of floater intrusions upon nest success (see Haller 1996). A stochastic population matrix model developed by Monzón and Friedenberg (2018) explored the floater dynamics of Moffat’s equilibrium (Hunt 1998, Hunt et al. 2017). Importantly, the rate of floater transition to the breeder stage was modeled dynamically so that transitions were determined by the availability of territories. Their model projected life-stage-structure and allowed computation of instantaneous floater-to-breeder ratios and rates of subadult nest occupancy in a hypothetical Golden Eagle (Aquila chrysaetos) population. The authors ran simulations of population decline and growth, habitat expansion and contraction, and valuably, the 10-yr cycling of a hypothetical prey population. Monzón and Friedenberg’s (2018) report emphasized that floater-to-breeder ratios and the incidence of subadult nest occupancy responded to these scenarios in ways indicating that neither, as a ‘‘snapshot metric,’’ can diagnose the status of a population in the absence of other information. For example, high instantaneous floater-to-breeder ratios characterized not only robust populations, but also those where territory occupancy was shrinking because of habitat loss. High rates of subadult occupancy manifested in both increasing and declining populations. In all, we found Monzón and Friedenberg’s (2018) modeling results consistent with Moffat’s equilibrium dynamics as described by Hunt (1998), Hunt and Law (2000), and Hunt et al. (2017). We believe that variations upon the authors’ algorithm can find useful application in studies of","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78678491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Book Review: Vultures of the World: Essential Ecology and Conservation","authors":"Matías A. Juhant, Evan McWreath, J. Burnett","doi":"10.3356/JRR-57-3-Book-Review","DOIUrl":"https://doi.org/10.3356/JRR-57-3-Book-Review","url":null,"abstract":"Vultures of the World: Essential Ecology and Conservation. By Keith L. Bildstein. 2022. Cornell University Press, Comstock Publishing Associates, Ithaca, New York, USA. ISBN: 978-1501761614. Hardcover, $25.29 and Kindle, $12.99. Dr. Keith Bildstein’s latest book, Vultures of the World: Essential Ecology and Conservation, provides an engaging look at vultures and condors, seeking to help us understand this widely recognized but underappreciated avian group. Bildstein is known to many Journal of Raptor Research (JRR) readers as a past Raptor Research Foundation Vice-President (1999–2002) and member of the Board of Directors (1988–1997). Bildstein is also a former Sarkis Acopian Director of Conservation Science at Hawk Mountain Sanctuary, Kempton, Pennsylvania, USA. His new book reflects the culmination of nearly two decades of personal experience observing and studying vultures worldwide, focusing on migration and movement behavior, physiology, and ecology of migratory and nonmigratory vulture species. We (MAJ, EM, and JB) appreciate the opportunity to review this book on vultures and condors, as the three of us study these full-time obligate scavengers in the western hemisphere. In his three-page preface, Bildstein makes two critical points that the new generation of vulture biologists should consider. The first point: Bildstein has broadened his perspectives over the decades by interacting with other research biologists, and without those interactions, this book could not have been written. Consequently, this point emphasizes the importance of humility and having or developing social abilities necessary to discuss the subjects of study with your peers. The second point: two monumental monographs by Brown and Amadon (1968) and Mundy et al. (1992) have provided an effective model to describe the essential ecology of these full-time obligate scavengers, facilitating Bildstein’s work on vultures at a global scale. The takehome message here is that regardless of the age of the reference, older literature can provide critical insight into the current knowledge of the subject of study. Vultures of the World provides thoughtful explanations to simple questions such as ‘‘Why are vultures the only full-time obligate scavengers in the vertebrate group? What physical and behavioral adaptations have evolved that allow them to inhabit a diverse set of habitats? How do vultures find and feast on rotting flesh?’’ Moreover, it provides helpful background on New World (family Cathartidae) and Old World (family Accipitridae) vultures. JRR readers may remember these terms refer only to the current species distributions and not their geographical origins, which is an important distinction, as Old World vultures may have evolved in the New World, and those we call New World vultures most likely evolved in the Old World. The scavenging habits of these two families are thought to have evolved independently, leading to adaptations such as large bodies, broad wings, power","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87556222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toward Rapid Population Assessment for Raptor Conservation: Subadults, Floaters, Strawmen, and Context. A Response to Hunt and Law","authors":"J. Monzón, Nicholas A. Friedenberg","doi":"10.3356/JRR-22-117","DOIUrl":"https://doi.org/10.3356/JRR-22-117","url":null,"abstract":"Many raptors exhibit life history characteristics that simultaneously place them at conservation risk and make them difficult to study, including delayed reproduction, long life spans, low annual fecundity, and large seasonal movements. Developing effective methods for rapid assessment of raptor populations will improve the feasibility and timeliness of adaptive management. To this end, we used a stage-structured demographic model to evaluate the insight into population decline risk provided by two population structure measurements: subadult nest occupancy and the ratio of non-territorial ‘‘floater’’ adults to territorial breeders (Monzón and Friedenberg 2018). Here, we respond to a commentary by Hunt and Law (2023) that addresses our study’s premises. There is no disagreement that the metrics require further context to be diagnostic; however, Hunt and Law (2023) offer three specific criticisms of our study, calling them strawmen. Although we did not intend them as such, discussing each criticism here offers an opportunity to clarify how these demographic metrics are and should be interpreted. First, Hunt and Law (2023) assert that we proposed, as a strawman, that subadult nest occupancy has only one possible explanation. They are referring to our summary of previously published work suggesting ‘‘a high incidence of subadults on nests might characterize a population in decline or at high risk of decline because it may be depleted of adult breeders and floaters’’ (Monzón and Friedenberg 2018, citing Balbontı́n et al. 2003 and Ferrer et al. 2003). Our summary reflects the preponderance of studies on the subject. Even Hunt and Law (2023), shortly after pointing out the narrowness of our summary, establish the general rarity of subadult nesting among raptors and assert that it should be regarded as a meaningful warning sign even if observed at a low level. With this premise as a hypothesis, we explored various ecological scenarios that can yield high rates of subadult nest occupancy and then assessed the value of this snapshot metric for indicating risk of population decline. The metric on its own was useful for identifying scenarios of moderate decline risk but failed to discern cases of low and high risk (Monzón and Friedenberg 2018). The examples presented by Hunt and Law (2023) all provide additional ecological context with which to interpret the metric properly and share the theme of high adult mortality being an important factor—the exact conclusion we reached in our original study (Monzón and Friedenberg 2018). In the example of Golden Eagles (Aquila chrysaetos) in the Altamont Pass Wind Resource Area in California, a high rate of subadult nest occupancy is interpreted in the context of high adult mortality from collisions with wind turbines (Wiens and Kolar 2021). Similarly, the","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88177034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nest Usurpation by a Female Mississippi Kite (Ictinia mississippiensis)","authors":"C. Boal","doi":"10.3356/JRR-22-103","DOIUrl":"https://doi.org/10.3356/JRR-22-103","url":null,"abstract":"Virtually all species compete for resources, which can lead to aggressive intraand interspecific interactions between individuals (Scott and Fredericson 1951). These interactions may take the form of displays, aggressive chases, and physical contacts (Jamieson and Seymour 1983, Bildstein and Collopy 1985, Boal 2001). Among conspecifics, these interactions may be agonistic, which is an escalation of behaviors from threat displays (often ritualized) to aggression, ultimately resulting in the submission or death of one combatant (McGlone 1986). For example, territorial Harris’s Hawks (Parabuteo unicinctus) engage in posturing, display, and eventual attack if an intruding conspecific does not leave (Dawson and Mannan 1991). In more extreme cases, individuals may kill and cannibalize conspecifics (Allen et al. 2020). The Mississippi Kite (Ictinia mississippiensis) is a highly social, quasi-colonial species (Skipper 2018, Parker 2020). For example, in 2022 I monitored 52 nests among 20 urban parks (one to eight nests/ park) in Lubbock, Texas, USA, and documented a mean density of one nesting pair per 2.7 ha (62.46 SD). Additionally, large nonbreeding groups may communally roost in trees near occupied nests. Despite such close proximities, aggressive interactions between Mississippi Kites appear to be exceedingly rare, with only a few documented events that usually consist of adults chasing subadults away from nests (Shaw 1985, Parker 2020). In summer 2020, I banded a nesting female Mississippi Kite with a US Geological Survey Bird Banding Lab aluminum leg band and a plastic green-colored band with the white letters ME (hereafter G-ME). I did not band the male of the breeding pair. The pair’s 2020 nesting attempt was successful in fledging one young. On 4 June 2021, I confirmed the female G-ME had returned to the 2020 nest area. The 2020 nest had blown out, but the kites had constructed a new nest and I observed multiple copulations between an unbanded male and G-ME. On 23 June 2021 at approximately 1020 H CST, I approached the G-ME nest to assess breeding status. At this date, all the monitored kite nests in my study were in the incubation stage. Upon my arrival I observed G-ME standing on the north side of the nest and facing an unbanded adult female Mississippi Kite perched in the cup of the nest (Fig. 1). The two kites posed with gaped beaks, nape feathers erected, and wings flared out as they faced each other. An unbanded adult male was perched on a branch approximately 1 m above and to the side of the nest. Although I did not know when the interaction was initiated, I watched for more than 10 min as the two female kites commenced to fight on the nest. They began making pecking strikes at each other, progressing to breast to breast contact and batting at each other with their wings and making pecking strikes toward each other’s faces (Supplemental Material 1). When one bird struck out with its beak, the other would retract its head backward to avoi","PeriodicalId":16927,"journal":{"name":"Journal of Raptor Research","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87306140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}