Page 47 - State of Biodiversity Report 2022/2023

Where do House Crows sleep at night – “Roost Site”
Article by: Mmatjie Mashao
Email: Mmatjie.Mashao@durban.gov.za
There is one misconception that all birds sleep in their nests. In actual fact, birds find safe, protected spots in trees, shrubs and vines to roost for the night. Some birds perch close to tree trunks on the downwind side, while others sleep in cavities or inside tree holes where they nest, others use roofs or just stand in water.
It is only during the breeding season that some/most adult birds will sleep in the nests at night to provide their eggs and chicks with needed warmth. Also, for protection against predators.
Now, where do House Crows sleep at night. House Crows find a sheltered place to roost. They often use tall trees with dense crowns and perch high in the tree foliage. House Crows roost communally in very busy areas with greater human activity. Here in Durban, House Crows found a
sheltered place at the Durban Cemetery (also known as West Street Cemetery) to roost. The Durban Cemetery is characterised by as being busy, surrounded by tall trees and buildings. It is bordered by a busy taxi rank, street vendors, muthi market and West Street which are all busy throughout the day making it a suitable roost site for them. Gum trees (Eucalyptus) are used by House Crows to roost. In groups, House Crows perch high in the tree foliage where they would spend the night and will only leave the site in the early hours of the next morning.
Before flying to the roost site, House Crows gather in small groups at various locations near the roost sites. Depending on the season, time of arrival at the roost site varies. At the Durban Cemetery House Crows started arriving between 16h30 and 17h30, just before sunset. They were observed arriving at the roosting site in groups of 10 to 50 birds. Also, they were observed to congregate on one roost tree until the number had grown too large that some birds would move to other roost trees. About four trees at this site are used by House Crows. This information has presented an opportunity for the observers to get a good estimate of the number of Crows within the city. From the Blue Lagoon in the North of Durban
to Isipingo in the South of Durban, all House Crow seems to fly to the cemetery to roost.
Increase in the number of House Crows is still a concern in the city. They are a thread to the ethekwini biodiversity, noisy and disruptive, known vectors of disease and highly invasive along coastal areas in Africa.
There is a chance that there are more House Crow roost site within eThekwini Municipality that observers do not know about. Any suspected site with the above-mentioned characteristics can be reported to the eThekwini surveillance group via email to: Mmatjie.Mashao@durban.gov.za
STATE OF BIODIVERSITY REPORT 2022/2023 45