Accuracy of Estimating Wolf Summer Territories by Daytime Locations

By Demma, Dominic J.; Mech, L. David | The American Midland Naturalist, April 2011 | Go to article overview

Accuracy of Estimating Wolf Summer Territories by Daytime Locations


Demma, Dominic J., Mech, L. David, The American Midland Naturalist


ABSTRACT. -

We used locations of 6 wolves (Canis lupus) in Minnesota from Global Positioning System (GPS) collars to compare day-versus-night locations to estimate territory size and location during summer. We employed both minimum convex polygon (MCP) and fixed kernel (FK) methods. We used two methods to partition GPS locations for day-versusnight home-range comparisons: (1) daytime = 0800-2000 h; nighttime = 2000-0800 h; and (2) sunup versus sundown. Regardless of location-partitioning method, mean area of daytime MCPs did not differ significantly from nighttime MCPs. Similarly, mean area of daytime FKs (95% probability contour) were not significantly different from nightime FKs. FK core use areas (50% probability contour) did not differ between daytime and nighttime nor between sunup and sundown locations. We conclude that in areas similar to our study area day-only locations are adequate for describing the location, extent and core use areas of summer wolf territories by both MCP and FK methods.

INTRODUCTION

Very high frequency (VHF) telemetry during daytime has been used to locate and observe wolves since the late 1960s (Mech, 1973). Telemetry projects typically locate wolves when conditions permit flying and observation of animals (Mech, 1973, 2009; Van Ballenberghe et al, 1975; Fritts and Mech, 1981; Peterson et al, 1984; Ballard et al, 1987; Fuller, 1989; Wydeven et al, 2009). These locations are used to estimate wolf-pack home ranges (usually MCPs or FKs) or territories. Because no study we are aware of has compared wolf spatial use during the day with that during the night using any method, wolf territories calculated using VHF locations might only be representative of wolf space use during daytime.

Global Positioning System (GPS) collars became available for wildlife research in the 1990s (Rodgers and Anson, 1994), and are now commonly used for wolf research. Because they can automatically collect large amounts of location data around the clock and in all weather conditions, they can provide an unbiased estimate of 24 h wolf-territory area and location, movement patterns (Merrill and Mech, 2003), prédation behavior (Derama et al, 2007), kill rates (Sand et al, 2008; Webb et al, 2008) and wolf home-range size (Mills et al, 2006) . However, we are unaware of any GPS-based comparisons between wolf home ranges determined at night versus day. Smith et cd. (1981) calculated coyote (Canis latrans) minimum convex polygon (MCPs) from VHF locations collected during daylight, half-night and full-night tracking periods, and concluded that home range sizes determined from >3 nights of hourly locations were considerably larger than those determined from daylight locations.

Because a large body of extant wolf information exists that relied on daytime VHF locations, an assessment is needed to determine if wolf location data collected only during the day represent only the extent of daytime use or whether these data represent both day and night use. Thus we used GPS telemetry to determine how daytime wolf locations compare to those of nightime locations and thus to assess the suitability of using wolf locations obtained by the more conventional daytime methods to characterize a wolf territory. Studies comparing results between different home-range-estimation methods have been published elsewhere and were not the focus of this study.

STUDY AREA

We conducted our study during Jun. through Aug. of 2003-2004 in a 2100-km area in the Superior National Forest (SNF) of northeastern Minnesota (48°N, 92°W). Nelson and Mech (1981) provided a detailed description of the study area. Wolves occurred throughout the study area at densities of 30-36/1000 km2 during the study (Mech, 2009). White-tailed deer (Odocoileus virginianus) occurred at densities of 12-15/10 km (M. H. Dexter, Minnesota Department of Natural Resources, unpublished report) and constituted the major prey of wolves in the area (Frenzel, 1974; Nelson and Mech, 1981, 1986), primarily fawns during summer (Van Ballenberghe et al, 1975; Nelson and Mech, 1986; Kunkel and Mech, 1994). …

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • A full archive of books and articles related to this one
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Accuracy of Estimating Wolf Summer Territories by Daytime Locations
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

    Already a member? Log in now.