Similarity index

In **Tables 2** and **3**, the similarity index has been calculated to show if there are noticeable time and seasonal differences in the calling activities between Malawi and The Gambia. The index used is modified from MacNaughton & Wolf's [6] "Index on Community Similarity":


Similarity Index 2 m / a b =∑ ∑ + ( ) ( )

*BO = Barn Owl; PSO = Pearl-spotted Owl; SwfO = Southern White-faced. Owl; NwfO = Northern White-faced Owl, and SEO = Spotted Eagle Owl.*

#### **Table 2.**

*Timing of the African owl calls as hourly percentage from the total calls.*

*The Vocal Activity of Twelve African Owl Species DOI: http://dx.doi.org/10.5772/intechopen.103887*


*BO = Barn Owl; PSO = Pearl-spotted Owl; SwfO = Southern White-faced. Owl; NwfO = Northern White-faced Owl, and SEO = Spotted Eagle Owl.*

#### **Table 3.**

*Timing of the African owl calls as monthly percentages from total calls.*

in which: a = percentage in Malawi, b = percentage in The Gambia, m = minimum percentage in either country. The nearer 1.0 the index is, the higher is the similarity between the countries and less important are the noted differences. Due to the nonsystematic nature of material collection, no further statistical tests were undertaken.
