Table 2 in A comparison of image and observer based aerial surveys of narwhal

Table 2. Summary of sightings by image analysts and/or aerial observers, with and without truncation at 500 m. Where both aerial observer pairs had the same sighting with different group size or perpendicular distance estimates, an averaged value was used.
OnlySighted bySighted bySighted bysight byOnlyimageimage analystimageSighted byimagesighted byanalystand/oranalystobserveranalystobserverand observerobserverNo truncationNo. of groups626334352897No. of animals1352276212488274Average group size2.23.61.83.53.12.8Average distance227580237839329454Truncation = 500 mNo. of groups62363482870No. of animals135126622488173Average group size2.23.51.83.03.12.5Average distance227269237329234247