Evaluating Agricultural Applications of Orchard Nest Boxes and Perches for a Declining Raptor Species: Quantifying Impacts on Pest Rodents and Birds

Project Overview

GNC15-211
Project Type: Graduate Student
Funds awarded in 2015: $9,959.00
Projected End Date: 05/01/2018
Grant Recipient: Michigan State University
Region: North Central
State: Michigan
Graduate Student:
Faculty Advisor:
Dr. Catherine Lindell
Michigan State University

Annual Reports

Commodities

  • Fruits: cherries

Practices

  • Pest Management: Nest Boxes

    Abstract:

    Management of pest species via a native predator is a sustainable practice that promotes natural predator-prey relationships in agroecosystems. Previous studies have shown that raptors can reduce rodent and bird prey abundances. The American Kestrel is a widespread species of falcon that has shown long-term population declines due in part to loss of natural nesting cavities; however, kestrels readily use nest boxes, which allow for breeding in areas that may provide valuable hunting habitat, such as agricultural areas. Farmers can therefore easily install these low-cost nest boxes to attract breeding kestrels. However, the use of kestrels for agricultural pest management has received limited investigation.

    New nest boxes installed in Michigan cherry orchards since 2012 have been used extensively by kestrels. We used nest box video cameras to determine that kestrels provision their nestlings with known orchard pests, including grasshoppers, voles, and fruit-eating birds; furthermore, we observed generalizable trends in kestrel prey removal based on nestling age, seasonal timing of prey availability, brood size and sex ratio, weather, and adult female movements relative to the nest box. We used transect surveys to determine that fruit-eating bird counts were lower in orchards with active kestrel nest boxes, thus kestrel activity associated with nest boxes likely acts as a reliable cue of predation risk that, in combination with direct consumption, reduces fruit-eating bird abundances in orchards. Finally, we previously used live-trapping to determine that summer small mammal abundances were lower in orchards with active kestrel boxes and orchards that had been more recently mowed; however, these differences did not carry over as differences in winter presence in orchards, when mammal damage to trees is most likely. We therefore present recommendations for future work on small mammal abundances in orchards.

    This project resulted in the installation of 25 nest boxes in cherry orchards throughout Leelanau County, MI and prompted an expansion of our nest box program into the blueberry-growing region of southwestern MI. Presentations at MSU Extension workshops and farmer expos reached dozens of cherry and blueberry growers in MI, and press releases about this project have the potential to reach growers nationwide. Ongoing research, funded by a National Science Foundation Dynamics of Coupled Natural and Human Systems Grant, will use a national survey of fruit growers and in-person interviews, along with modeling approaches, to investigate factors that influence grower adoption of predator nest boxes as a pest management practice.

    Project objectives:

    Objective 1) Effects of kestrel nest boxes and supplemental perches on kestrel presence and fruit-eating bird abundances in orchards:

    A 2014 telemetry study of orchard use suggests that kestrel activity in orchards is based on activities at the nest box rather than consistent hunting in the orchard. I hypothesized that a lack of suitable perches, especially in young, open orchards with small trees, limits orchard use by kestrels. Furthermore, I hypothesized that increased kestrel presence will increase predation pressure on prey bird species.

    Objective 2) Effects of kestrel nest boxes and supplemental perches on winter rodent abundances in orchards:

    Small mammal trapping that I conducted in 2014 indicates that Microtus voles are not present in high numbers in orchards during the summer; however, I hypothesized that snow cover provides adequate cover for voles in will result in higher abundances in the winter, when damage to trees is most likely. I used small mammal camera traps to determine the effect of summer kestrel presence in nest boxes and the continued winter presence of perches on winter small mammal abundance in orchards.

    Objective 3) Estimating number of prey removed and extent of prey removal by kestrels breeding in orchard nest boxes:

    I estimated the prey removal efforts of kestrels using orchard nest boxes and develop models that can predict the number and types of prey that breeding kestrels will capture, as well as the size of the area from which prey will be captured.
     
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.