Feral Horse Counts

2018 Feral Horse Survey Count Summary

Survey Time Period: January 2018

Areas Covered: Brazeau, Clearwater, Elbow, Ghost River, Nordegg and Sundre Horse Capture Areas

Number of Horses Counted: 1721

Summary Reference:

Alberta’s 2018 feral horse count is complete. The 2018 feral horse count was completed over the first two weeks of January.

A total of 1721 individual feral horses (including adults, sub-adults/yearlings, and foals) were observed during the course of the minimum counts. Counts by Horse Capture Areas are shown in the summary reference above. This method of surveying is considered a total minimum population and represents the absolute minimum amount of feral horses on the landscape. Feral horses are known to exist in all zones but some animals may have been missed on the day of counting.

For the second year, Sundre and Ghost Horse Capture Areas were flown with both total minimum count and distance sampling methodologies. Distance Sampling is a common method used for conducting wildlife surveys and provides more statistical rigour when considering population changes across years. Analysis from this method provides an estimated total number of horses in each of the zones based on the number of horses observed during the flight. The 2018 distance sampling analysis supports our minimum count numbers, estimating an increase in the number of feral horses in the Horse Capture Area compared to last year.

Changes from Previous Survey Counts

The total minimum count of feral horses in the Capture Areas has been increasing and may be influenced by a combination of factors:

Count Methodology

  • A need for more detailed understanding of feral horse population numbers has emerged as the number of horses being captured decreases and the population increases. Prior to 2013, only areas where feral horses were known to be were primarily flown. Between 2013 and 2016, only the Sundre, Ghost, and Elbow Horse Capture Areas were flown consistently for minimum counts. Since 2016, total minimum count of all six Horse Capture Areas has been performed, with adult horses and yearlings (sub-adults) differentiated.
  • The 2018 survey was completed in January to align the time of year with other species surveyed by the department, such as moose and elk. This timing was 2 months earlier than the previous year’s survey. This change of season could result in a higher count of feral horses because:
    • The snow cover at this time of year makes detection of animals easier, and;
    • Additional natural mortality (dependent on harsh weather conditions) is possible between January and March.
  • The flight paths may change slightly from year to year to ensure the department accurately captures feral horse land use. This change in path is because total minimum counts focus on flying areas preferred by feral horses. Cutblocks and industrial clearings have been noted as areas horses prefer. However, that preference may wane as these cutblocks fill back in with trees and produce less forage over time. This response by the feral horses lowers the priority to fly cutblocks as they mature, and results in some change to flight paths over time. Grassy meadows and shrublands are also areas of choice for feral horses, which have a much more consistent supply of forage, so flight paths over these areas do not change much.
  • The additional use of distance sampling methods provides statistical rigor and allows the department to assess changes in population size more effectively. The results of the distance sampling analysis agree with the total minimum counts that the number of feral horses has seen an increase since last year’s count.

Weather Conditions and Timing

  • Alberta has been experiencing milder winter conditions that are suitable for more feral horses (foals and adults) to survive the winters, reproduce, and contribute to the growing numbers.

Illegal Release of Domestic Horses

  • The increase in feral horse numbers from 2017 to 2018 may not be due to a successful reproductive rate and low mortality alone. Release of horses is illegal according to Section 16 of the Forest Reserves Regulation and inhumane and should be reported to a local Alberta Environment and Parks office if seen.

How Feral Horse Survey Counts are Conducted

Minimum Counts

Feral horse surveys were conducted using a rotary-wing aircraft (helicopter) for greater maneuverability. During the count, a group of horses will be circled until the observers can completely count the number of horses in the group. This total number is then divided up into adults, sub-adults (yearlings) or foals. GPS points and pictures are taken of every animal detected to prevent double counting.

If the observers are unsure if a horse is a yearling or a small adult, it is classified as an adult to minimize the risk of overestimating the number of yearlings.

Distance Survey

Feral horse distance surveys are also conducted using a rotary-wing aircraft (helicopter). Before flying, GIS staff overlay theoretical flight transects (2-10 km long) on the capture areas. Next, they delete 49% of the transect lines randomly, leaving 51% of the transects to be flown.

When flying, three observers are assigned specific areas within their field of view to look for animals (50 m on either side of flight transect or 50 m - 2 km on either side of the transect line). GPS points are taken on the flight transect at the moment when animals are observed and above the location of the group. These points are used to create a detection function. Based on the number of animals detected and the number of animals within each group, the detection function can be used to provide an estimate of the number of animals on the landscape. This number is important as it gives an actual estimate of the number of animals within an area with confidence intervals, which are used to determine if there are significant changes in the population.

For more information on distance sampling methodology, see the following resources:

Buckland, S.T., Anderson D.R., Burnham, K.P., Laake, J.L., Borchers, D.L., and Thomas, L. (2001). Introduction to Distance Sampling, Oxford University Press, Oxford.

Thomas, L., Buckland, S.T., Rextad, E.A., Laake, J.L., Strindberg, S., Hedley, S.L., Bishop, J.R.B., Marques, T.A., and Burnham, K.P. (2010). Distance software: design and analysis of distance sampling surveys for estimating population size, Journal of Applied Ecology 47, 5-14.

Population Metrics

When managing native wildlife such as elk, staff in wildlife management consider the recruitment rate of a wildlife population to be the number of young per 100 females that survive to one year of age. When it comes to feral horses, we know that only part of the total population is female, but we do not currently have a ratio of males to females. Our current survey method also underestimates the number of young animals, so this makes it very difficult to determine a true recruitment rate.

We currently break down the percent of the total population that are sub-adults to create a more conservative population growth estimate that is relative to all animals, male and female.

To use the Sundre Equine Zone as an example, there were a total of 1015 horses counted:

  • 789 adults
  • 225 yearlings
  • 1 foals

This means that yearlings made up 22% of the total population (not including 2018 foals) with a ratio of 29 yearlings per 100 adults. This is not a true recruitment rate, but gives a rough idea of how many foals are surviving to become yearlings and helps predict the population growth rate.

Past Survey Count Summaries

Review previous years’ maps and charts summarizing the results of Alberta’s feral horse survey counts. Survey counts are conducted annually in the province’s Horse Capture Areas.

The survey counts can be found on the Open Government Portal at:

The years provided on the Portal are as follows:

  • 2018 Feral Horse Survey Count Summary
  • 2017 Feral Horse Survey Count Summary
  • 2016 Feral Horse Survey Count Summary
  • 2015 Feral Horse Survey Count Summary
  • 2014 Feral Horse Survey Count Summary
  • 2013 Feral Horse Survey Count Summary

 

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Updated: Sep 21, 2018