The influence of night length: Activity of the northern bat Eptesicus nilssonii under conditions of continuous light in midnight sun compared to a southern population

Table 1 Number of recordings by the three different recording techniques used at various roosts and sites

Roost/Region	Technique	Exits	Returns	Passes	Calls	Minutes	Nights
Løvhaug	Visual counts	6578	4181				123
Troms, excl. L. Løvhaug	Visual counts	3283	1891				162
Saltdal [2]	Visual counts	648	746				24
Løvhaug	IR detection			26723			174
Bardu	IR detection			2465			49
Saltdal [1]	IR detection			6121			65
Troms, all sites	Ultrasound				204680		250
Frafjord, all sites	Ultrasound					12180	385

Løvhaug and Bardu are single roosts, Saltdal is either 1 or 2 roosts, Troms is multiple roosts, Frafjord represents multiple hunting sites. Nights is the number of nights the technique was in operation

ISSN: 2056-3132