Journal Article ADAPTIVE SIGNIFICANCE OF DELAYED PLUMAGE MATURATION IN MALE NORTHERN ORIOLES Get access Nancy J. Flood Department of Zoology University Toronto Ontario M5S 1A1 Canada Search for other works by this author on: Oxford Academic Google Scholar Evolution, Volume 38, Issue 2, 1 March 1984, Pages 267–279, https://doi.org/10.1111/j.1558-5646.1984.tb00285.x Published: 01 1984 history Received: 29 1982 Revision received: 21 June 1983

To avoid energy allocation conflicts, birds generally separate breeding, migration and moult during the annual cycle. North American passerines typically on breeding grounds prior to autumn migration. However, some have evolved a moult-migration strategy in which they delay until stopping over Rohwer et al . (2005) proposed ‘push–pull hypothesis' as an explanation for evolution of this strategy, but it has not been empirically tested. Poor conditions at end summer would push depart moult,...

Spatial proximity is an important metric in cattle behaviour, which used to study social structure, dyadic relationships, as well grazing and maternal behaviours. We developed efficient, novel, non-invasive method quantify the spatial of beef by using UAV-based image acquisition photogrammetric analysis. Orthomosaics constructed images obtained from UAVs were measure, with accuracy ±1.96 m (95% likelihood), inter-individual distances between cows calves. Aerial videos calves their dams, held...

Abstract Urbanization is changing natural landscapes worldwide, pushing species to quickly acclimate or adapt if they are survive in urban environments. Mountain chickadees (Poecile gambeli) readily nest both and rural environments without suffering apparent reproductive costs. However, whether urban-nesting successful these due differences behaviour between birds remains untested. We examined the behavioural responses of nesting mountain chickadee females when presented with a novel object...

Many studies have shown that the plumage coloration of male birds can act as an honest signal quality, indicating benefits a female could gain from pairing with specific male. In some species, females also display ornamental plumage, but less is known about function and potential adaptive significance because most research has focused on coloration. Male Mountain Bluebirds (Sialia currucoides) full body, ultraviolet (UV)-blue whereas more subdued, blue color rump, wing, tail. During 2011...

Field studies were conducted at six lakes in southern Ontario to investigate the effects on breeding bird populations of disturbance caused by recreational use shorelines.The degree land development observed created extensive edge habitat but had only moderate other vegetation characteristics.Although disturbed areas significantly more birds, they tended have lower species diversity than natural areas.Species richness remained fairly constant both and isolated study whereas evenness was...

Many songbirds are under increasing pressure owing to habitat loss, land-use changes, and rapidly changing climatic conditions. Using citizen science data collected from 1980 2014, we asked how local weather regional climate influenced the breeding dynamics of Mountain Bluebirds (Sialia currucoides (Bechstein, 1798)) Tree Swallows (Tachycineta bicolor (Vieillot, 1808)). Bluebird reproduction was strongly associated with weather: number nestlings fledglings both decreased in years high...

Sexual selection and mate choice are dynamic processes that can be influenced by a variety of environmental social factors, which have been well studied in range taxa. However, humans, the factors influence regional variation preference for attributes remain poorly understood. In addition, underlying based on individual age may strongly preferences. this study, we examined written descriptions preferred mates from online dating profiles 1111 women 26 cities across Canada. We grouped words...

Abstract Carotenoid‐based plumage coloration plays a critical role for both inter‐ and intrasexual communication. Habitat diet during molt can have important consequences the development of ornamental signals used in these contexts. When occurs away from breeding grounds (e.g., pre‐alternate on wintering grounds, or stopover molt), discerning influence habitat be particularly important, as effects may result carryover that territory acquisition mate choice subsequent seasons. Several species...

Sex allocation theory predicts that females should bias the sex ratio of their offspring in response to differences reproductive value sons versus daughters. Consistent with this prediction, many species appear ratios mate attractiveness and condition. Male mountain bluebirds ( Sialia currucoides ) display full body UV-blue structural plumage colouration, which is associated attractiveness, condition, success. Over four breeding seasons, we found paired more colourful males produced...

Abstract Environmental factors affect migratory animal populations in every phase of their annual cycle and have significant impacts on breeding success survival. The Breeding Bird Survey provides a long‐term database for examining population trends North American birds, allowing us to examine large‐scale environmental that influence abundance. We examined plant productivity as measured by normalized difference vegetation index (NDVI) over 24‐year period from 1983–2006 bird conservation...

The lodgepole pine dwarf mistletoe, Arceuthobium americanum, a common parasite found in western Canadian forests, causes significant yearly timber loss. purpose of this work was to determine if mistletoe infection affects the anatomy and morphology its needles. Needles were collected from infected, highly-broomed trees visibly uninfected (control) trees. Differences dimensions needles vascular cylinder, fresh weight, number stomata per unit surface area (density), size stomata, stomatal...

Abstract Spatial and temporal shifts in the migratory patterns of birds have become more frequent as climate change habitat alteration continue to impact ecosystems species dependent on them. In this study, we used eBird community science data collected over ten years examine potential changes three North American bluebird species: eastern ( Sialia sialis ), western mexicana mountain currucoides ) bluebirds. Community datasets such those provided through are a valuable tool for examining...

Arceuthobium americanum Nutt. ex Engelm. (lodgepole pine dwarf mistletoe) is a dioecious plant parasitizing conifers in North America. Here, we documented changes the “taxonomic richness” of culturable endophytic fungi male and female A. over growing season. Endophytic were isolated from vegetative stems surface-sterilized aerial shoots collected weekly April to September. Isolated characterized macroscopically, generating database 48 morphologically unique forms that likely represented...

Abstract We investigated the influence of conspecific and heterospecific neighbours on reproductive success mountain bluebirds ( Sialia currucoides ) tree swallows Tachycineta bicolor over eight breeding seasons. The abundance was negatively associated with in but positively during early nesting period (i.e., hatching rate). For bluebirds, neighbour higher fledging rate) later stages period; same true for swallows. These findings could be explained by either positive behavioural interactions...