Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis

Supplemental feeding is a common anthropogenic influence on wildlife which, dependent on natural food availability, can have positive or negative effects on physiological condition. For example, animals may respond negatively to supplemental feeding if the artificial food source increases disease ex...

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Main Authors: Danielle C. Perryman, Meelyn M. Pandit, Eric A. Riddell, Tiana L. Sanders, Ian A. Kanda, Jennifer L. Grindstaff
Format: Article
Language:English
Published: Wiley 2022-07-01
Series:Journal of Avian Biology
Subjects:
Online Access:https://doi.org/10.1111/jav.02920
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author Danielle C. Perryman
Meelyn M. Pandit
Eric A. Riddell
Tiana L. Sanders
Ian A. Kanda
Jennifer L. Grindstaff
author_facet Danielle C. Perryman
Meelyn M. Pandit
Eric A. Riddell
Tiana L. Sanders
Ian A. Kanda
Jennifer L. Grindstaff
author_sort Danielle C. Perryman
collection DOAJ
description Supplemental feeding is a common anthropogenic influence on wildlife which, dependent on natural food availability, can have positive or negative effects on physiological condition. For example, animals may respond negatively to supplemental feeding if the artificial food source increases disease exposure or there may be negative consequences from removal of a supplemental food source. We manipulated supplemental food availability in a wild population of eastern bluebirds Sialia sialis to examine the influence on body mass, physiological metrics and nesting success. Adult and nestling bluebirds were randomly assigned to one of three feeding groups. The first treatment group received mealworm Tenebrio molitor larvae inside nest boxes throughout the breeding attempt, the second treatment group received mealworms from nest completion until nestlings hatched, and the third treatment group received no supplementation. We collected blood samples from adults and nestlings to quantify bacterial killing ability, corticosterone levels and heterophil to lymphocyte ratios. As measures of nesting success, we quantified hatching success and fledging success. Supplement group tended to impact nestling mass near fledging; however, neither the physiological metrics nor the nesting success metrics differed significantly among experimental groups. Our results suggest eastern bluebird supplementation is largely neutral with the exception of its removal at the time of hatching, at least when natural food sources are abundant. Bird feeding by hobbyists may attract birds to locations with available nesting sites without demonstrably negative or positive effects, unless practiced inconsistently during breeding.
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spelling doaj.art-3769bc89671a40dca5ea32ebbb3847532022-12-22T04:01:42ZengWileyJournal of Avian Biology0908-88571600-048X2022-07-0120227n/an/a10.1111/jav.02920Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialisDanielle C. Perryman0Meelyn M. Pandit1Eric A. Riddell2Tiana L. Sanders3Ian A. Kanda4Jennifer L. Grindstaff5Dept of Integrative Biology, Oklahoma State Univ. Stillwater OK USADept of Integrative Biology, Oklahoma State Univ. Stillwater OK USAMuseum of Vertebrate Zoology, Univ. of California, Berkeley Berkeley CA USADept of Natural Resources, Ecology and Management, Oklahoma State Univ. Stillwater OK USACenter for Veterinary Health Sciences, Oklahoma State Univ. Stillwater OK USADept of Integrative Biology, Oklahoma State Univ. Stillwater OK USASupplemental feeding is a common anthropogenic influence on wildlife which, dependent on natural food availability, can have positive or negative effects on physiological condition. For example, animals may respond negatively to supplemental feeding if the artificial food source increases disease exposure or there may be negative consequences from removal of a supplemental food source. We manipulated supplemental food availability in a wild population of eastern bluebirds Sialia sialis to examine the influence on body mass, physiological metrics and nesting success. Adult and nestling bluebirds were randomly assigned to one of three feeding groups. The first treatment group received mealworm Tenebrio molitor larvae inside nest boxes throughout the breeding attempt, the second treatment group received mealworms from nest completion until nestlings hatched, and the third treatment group received no supplementation. We collected blood samples from adults and nestlings to quantify bacterial killing ability, corticosterone levels and heterophil to lymphocyte ratios. As measures of nesting success, we quantified hatching success and fledging success. Supplement group tended to impact nestling mass near fledging; however, neither the physiological metrics nor the nesting success metrics differed significantly among experimental groups. Our results suggest eastern bluebird supplementation is largely neutral with the exception of its removal at the time of hatching, at least when natural food sources are abundant. Bird feeding by hobbyists may attract birds to locations with available nesting sites without demonstrably negative or positive effects, unless practiced inconsistently during breeding.https://doi.org/10.1111/jav.02920bacterial killing abilitybird feedingcorticosteroneleukocyte ratioreproductive success
spellingShingle Danielle C. Perryman
Meelyn M. Pandit
Eric A. Riddell
Tiana L. Sanders
Ian A. Kanda
Jennifer L. Grindstaff
Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
Journal of Avian Biology
bacterial killing ability
bird feeding
corticosterone
leukocyte ratio
reproductive success
title Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
title_full Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
title_fullStr Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
title_full_unstemmed Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
title_short Effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds Sialia sialis
title_sort effects of supplemental feeding on nesting success and physiological metrics in eastern bluebirds sialia sialis
topic bacterial killing ability
bird feeding
corticosterone
leukocyte ratio
reproductive success
url https://doi.org/10.1111/jav.02920
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