Monday, 27 October 2014

Cameras from BirdLife SA to monitor Birds drinking in the Fynbos

A big thanks to Dale Wright and BirdLife South Africa for the loan of two Cuddeback Attack IR cameras which will be used to monitor drinking activity of birds at various water sources around Blue Hill Nature Reserve.

The following is a summary of the study proposal:

Temporal and environmental patterns of visitation at fresh water drinking sites by birds in a semi-arid Fynbos environment

Canaries and many other species of birds, especially granivores, need to modify their diets (Carrillo, Moreno et al. 2007) or supplement their water requirements in order to maintain body water balance (MacMillen 1990). Water supplementation may be from dew or residual rainfall, but in arid environments often birds need to drink from streams or other water supplies (Skead 1975). Global climate-change models suggests the Mediterranean climate of the Western Cape will become drier (Midgley, Hannah et al. 2002). There is also concern over the lowering of water tables due to ground water extraction, which may be influencing above ground water availability in the Western Cape (CapeNature pers comm). Cape Sugarbird, Orange-breasted Sunbird, Cape Siskin and Protea Seedeater have all been observed drinking water to some degree (Hockey, Dean et al. 2005), however, the reliance on water sources by the Fynbos endemic bird species has not been quantified. This project aims to determine temperature patterns and rainfall events influence the numbers of birds drinking at pre-identified drinking sites. The results have implications for the conservation of water supplies and Fynbos endemic birds across the Fynbos.

Methods

This project will take place in and around the Blue Hill Nature Reserve, Western Cape, an ideal location as it is juxtapositioned between arid Karoo environments and moister Fynbos. It thus experiences an extreme range of temperatures, from below freezing to 40 oC which will allow comparisons over a range of temperatures.

As observations need to be taken over a long period, through temperature extremes uncomfortable to human observers, we have chosen to undertake long-term monitoring via camera trapping. 

A number of regularly visited drinking sites have been identified. Cuddeback Attack camera traps have been installed at two of these. They have been set to take photos every 15 minutes automatically through the day. Photographs will be examined for the presence of drinking or bathing birds. The numbers of birds observed will form a relative index of water requirements for each species. Daily and seasonal trends can then be examined in relation to ambient and seasonal temperatures.


Example of camera installed on a drinking seep where various bird species have been observed drinking

We will initially model total drinking birds per day as a function of daily temperature (mean and maximum), daily temperature of previous day, time in days since last rainfall (by rainfall amount categories), mean daily wind, mean daily humidity, and month (season) using linear modelling or other appropriate modelling techniques.

We do wish to cross validate results for a selected period of time by having human observers undertake real time observations at these sites. This will help quantify the index in terms of real numbers of birds visiting drinking sites.

Literature cited

Carrillo, C. M., E. Moreno, F. Valera and A. Barbosa (2007). Seed selection by the trumpeter finch, Bucanetes githagineus. What currency does this arid-land species value? Annales Zoologici Fennici, Helsinki: Suomen Biologian Seura Vanamo, 1964-.

Hockey, P., W. R. J. Dean and P. Ryan, Eds. (2005). Roberts birds of southern Africa. Johannesburg, Trustees of the John Voelcker Bird Book Fund.

MacMillen, R. E. (1990). "Water economy of granivorous birds: a predictive model." Condor: 379-392.

Midgley, G., L. Hannah, D. Millar, M. Rutherford and L. Powrie (2002). "Assessing the vulnerability of species richness to anthropogenic climate change in a biodiversity hotspot." Global Ecology and Biogeography 11(6): 445-451.

Skead, D. M. (1975). "Drinking habits of birds in the central Transvaal bushveld." Ostrich 46(2): 139-146.







Figure 1 Cape Siskin at a drinking site, Blue Hill Nature Reserve

Figure 2 Male Yellow Canary drinking, Blue Hill Nature Reserve




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