Conducting a population estimate of overwintering monarch butterflies, Danaus plexippus Linnaeus, 1758, at California winter sites traditionally involves many early morning hours of using binoculars to count the insects as they cluster in tight aggregations among the high foliage of trees. This study investigates the effectiveness of counting the butterflies by using photographs of specifically selected clusters. Counts based on photographs of ten clusters from each of three overwintering sites were compared to counts of the same clusters using binoculars. The data were analyzed using mixed model analysis of variance (ANOVA). The results show that the photograph-based counts were equivalent to the binocular counts within ±10%.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.