Daubenton's local distribution, foraging areas & social networks

East lagoon

 

During harp trapping at Thames Water Sewage Works during 2016/17 we found pregnant female Daubenton's bats at both the Western and Eastern lagoons (the latter is the Hogsmill Sewage Works Nature Reserve).

These were interesting new records as this species has not been recorded at either site before. It was generally considered there was too much light pollution over the eastern lagoon.

Subsequent surveys did not record any Daubenton's bats and pipistrelles were able to see the harp traps before they were caught due to increased security lighting from Berrylands station and Thames Water's compounds.


Male bats particularly are not tied to the maternity colony  and can be fairly footloose. We found trees used for roosting during at Hampton Court and Bushy parks.

West lagoon

 

 

Tree-dwelling species typically change their roost every few days making it difficult to study them. When the males change roosts they can do so as 'singles' or as a group but are more solitary in their 'bachelor' colonies than others in the same genus such as Natterer's bats.

While the females stick together and keep a relatively strong social structure, males will roost with Daubenton's bats from other social groups.The roosting areas used by female groups of Daubenton's bats is very small, perhaps 17 hectares, with little overlap.

Harp trap

 

The foraging areas are much wider. The researchers from the Centre for Ecology and Hydrology at Wallingford and the Universities of Oxford and Exeter concluded that as groups use very small areas for their roosting needs, this species is vulnerable to even minor habitat changes.

Nathusius' pipistrelle bat