Factors affecting nest predation artificial and real Sagebrush Brewer’s Sparrow (Spizella breweri breweri) nests in the South Okanagan and Similkameen Valleys, British Columbia
Notice bibliographique
Résumé
Predation is the predominant cause of nest failure for the Brewer's Sparrow (Spizella breweri breweri; BRSP), a provincially red-listed shrub-steppe species that has experienced significant declines throughout most of its range (Breeding Bird Survey). The factors that influence nest survival are often species and context specific. Therefore, it is important to examine the dynamics of Brewer's Sparrow nest survival in British Columbia (BC) so that appropriate management strategies can be devised. I monitored Brewer's Sparrow nests to test if nest density and avian nest predator activity influenced Brewer's Sparrow nest survival. I also conducted an artificial nest experiment to assess potential nest predation risk relative to Brewer's Sparrow abundance and to determine whether increased avian nest predator activity was associated with reduced nest survival. In addition, within site factors such as tree encroachment, timing, and nest concealment were modelled to determine their effects on the survival of real Brewer's Sparrow nests at all nesting stages and for three nest predator categories - avian, mammalian and pooled (all predators combined) using artificial nests. The study was conducted at six sites in the South Okanagan region of BC. My results showed that increased avian nest predator activity was associated with reduced survival of artificial nests. Avian predation of artificial nests was also highest at sites with few Brewer's Sparrows, suggesting that Brewer's Sparrows may avoid nesting at sites with many avian nest predators. Artificial nest predation by small mammals did not vary with Brewer's Sparrow abundance. Survival analysis revealed that nest initiation date was an important predictor of real nest survival, because depredation increased later in the season. Pooled predators and mammalian depredation of artificial nests mirrored this trend. Avian predation risk was reduced through the season but only in combination with less nest cover. Late in the season, artificial nests placed close to trees experienced less mammalian predation and more avian predation. Tree density was related negatively to the survival of real Brewer's Sparrow nests at the nestling and pooled nesting stages. Overall, my results suggest that Brewer's Sparrows nested in sites lower in avian nest predator activity. This trait resulted in the relative importance of other predators, such as small mammals, becoming more apparent. The importance of nest concealment and tree encroachment on real nest survival may be circumvented by Brewer's Sparrows nesting far from trees, in micro-sites with ample cover, and nesting in sites with low avian nest predator activity.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».