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.
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
f
Thanks to share this post.temperature monitoring camera is a very good product.
ReplyDelete