Searching for the Peninsula’s Knysna Warblers in an attempt to save them from extinction in Cape Town

The Knysna Warbler can be considered as a classic Little Brown Job or“LBJ”. They are fairly small, mostly brown, skulking birds which are rarely seen. See figure 1. However, they have a distinctive and loud call which betrays their presence, especially in early spring. The Knysna Warbler is endemic to South Africa and is classified as Vulnerable. In Cape Town the population of Knysna Warblers occur on the lower eastern slopes of the Table Mountain chain occurring roughly from Tokai to Newlands. They occur mainly in thicket vegetation along the Greenbelts.

Knysna Warbler. Photo by Trevor Hardaker

Knysna Warbler. Photo by Trevor Hardaker

It has long been recognised that the Knysna Warbler is in a state of decline on the Peninsula. A fair deal of work was done on the subject by the late Prof Phil Hockey and Brent Visser whose research indicated that the main causal factor for the decline of the Knysna Warbler locally, was a change in habitat structure due to a change in the fire regime in their habitat. Basically, the thicket vegetation which they need is slowly changing into forest with insufficient understory.  The result is that the birds are making greater use of the greenbelts and large gardens which still have dense tangles and thickets. There may however be other causal factors which are contributing to the decline of the species locally.

The Cape Bird Club Conservation Committee is keen to work in collaboration with the City of Cape Town to see what can be done to prevent the very likely possibility that the Knysna Warbler could become locally extinct in the City of Cape Town.

An important component of managing the Knysna Warblers on the Peninsula is to know where they currently still occur and how many are left. This important baseline data will be invaluable in deciding on any management interventions in time.  A critical management intervention is to annually assess the number of remaining birds so that we can monitor the population. As the vast majority of these greenbelts are very well utilised by the public, we would like to request that anyone who hears a Knysna Warbler please report the date, locality and number of birds to Cliff at suncus@telkomsa.net

Listen to the bird call  Credit:  Simply Birding (the recording is copyrighted)

David Whitelaw
Cape Bird Club Conservation Committee

This info was received via WESSA.