Sightings Reports by IndividualsPublic Moose Pictures July 2009 - October 2009
Public Moose Pictures October 2009 - October 2010
We’ve analyzed all 730 reported moose sightings through September 30, 2010. In 703 reports, 984 total moose have been reported with 432 of those being cows, 233 calves, 239 bulls, and 80 unknown. Since we began receiving public reports of moose we’ve noticed some interesting trends. We have occasionally followed up on sightings reports by contacting individuals, but have not done anything else to confirm validity of a report.
We include points on maps below, and it is possible that you will see a moose along the roadside while driving. These reports are from a period of 16 months and show the patterns of people seeing and reporting moose. It is not possible to predict when an individual moose will be on the road, and there have been many times we have driven though these roads and not seen a moose.
The northeast moose sightings are broken down into reports from inside the BWCAW (brown), reports within the annual aerial survey grid (green), and moose sighted outside of the survey grid (blue). Thus far, about 45% of moose reports have been reported from outside what is considered core moose range in the state. Sightings from northwest Minnesota account for approximately 10% of reports. Within the northeast region about 18% of reports come to us from the BWCAW while 46% come from other parts of the core range, mostly within the Superior National Forest. Sightings from outside of core range in the northeast account for about 27% of reports. The number of reports outside of core moose range may be a result of those areas having a larger human population than within core range, and so moose are observed and reported more frequently than would be expected. People may be more likely to report moose sightings from outside the core range because it is more unusual to see a moose along the southern edge of the range in the state.
We’ve also noticed that during 2009 (the first full year of this reporting website’s existence) most moose were reported between May-October (88%), the time of year when many Minnesota residents and visitors are out enjoying summer by spending time on the roads, in the woods, and on the lakes. During 2009, 23% of moose sightings occurred in August, 21% were reported in September, and 17% were reported in July. Although we have sightings from each month of the year, very few moose were reported during the winter months.
Also interesting, but not entirely surprising, is that most reports outside of the BWCAW come to us from roadside sightings. State highways and interstates are included on the map and green points indicate a moose report.
Counting points within a restricted area surrounding both sides of state highways, federal highways, and county highways helped us determine how many moose sightings have occurred on or near roads within a portion of the northeast moose range. Purple points show those sightings on or near roads. Depending on the size of the area included on either side of a road (200 m, 400 m, and 600 m), between 28-40% of all moose sightings are from roadside reports in this portion of the state. There is some position error with these locations and some sightings may have been further or closer to roads than are seen here. However, when road names are mentioned specifically in the location descriptions of reports we assume that those moose were seen on or near those roads and so mapped those points accordingly.
After over a year of sightings reports, we can identify some trends and make some calculations on the submitted pictures. For example, from June to September in 2009 the calf:cow ratio was 0.46 in the reports submitted. From June to September in 2010 the calf:cow ratio was higher at 0.69. The reported ratios of 0.46 and 0.69 from the sightings reports are higher than the calf:cow ratios of about 0.30 in recent annual moose surveys in January (Lenarz 2010). It will be interesting to see if the higher calf:cow ratio in the sightings reports in 2010 is mirrored by a higher calf:cow ratio in the aerial moose survey in January 2011.
The ratio of calves to all moose seen in reports also increased in the sightings reports, from 0.22 in 2009 to 0.30 in 2010. The corresponding ratio in recent years in the aerial survey has been about 0.14 (Lenarz 2010)
Among the potential limitations to this sort of data from a statistical perspective is the sampling design. It is not random, and individuals or moose may cause biases. For example, multiple sightings may be reported by the same individual (don’t let this stop you from reporting a sighting), or the same moose might be reported by multiple individuals. While these are potential problems, we do not appear to have sightings reports overlapping in both time and space, and the reasonable calf:cow ratios indicate that these public sightings reports can be useful!
Sightings Reports by IndividualsOf the 730 sightings reports we have so far, most come to us from people who have only submitted a report one time. About 15% of the time we get more than 2 sightings reports from the same person reporting different moose sightings.