In recent years, a new method was put into practice in order to obtain the number of young godwits that fly out every year in the Netherlands estimates. The purpose of this is to keep the holes of the development of the breeding success of the Dutch population grutto . It is known that an inadequate breeding success is the main cause of the sharp deterioration of the godwit .
Godwit color ring , Jouke Altenburg )
Method to calculate the total number of fledged godwits
The method makes use of observations on stopping after the breeding season , in combination with the fact that in recent years there grutto chicks in the Netherlands, are provided with colored rings. After fledging these color-ringed birds mingle among their non -ringed species in the staging groups , which can be determined what proportion of young birds color rings wear . The " color ring density ' in these samples , multiplied by the total number of pups in that year was ringed , provides an estimate of the total number of black-tailed godwit guy that's flown in the Netherlands. Divided by the number of breeding pairs in the Netherlands, the estimated number of pups , the number of fledglings can be calculated . Per breeding pair
Breeding success too low
In 2013 275 chicks were ringed in total , of which 143 (52 % ) in southwest Friesland and 49 elsewhere in the province (including Ameland , Friesland total of 70% ) . From June to August 2013 are distributed by volunteers in Netherlands groups staging young godwits for the presence of color-ringed birds . Each group perceived they scored , including the total number of young godwits and the number thereof wore color rings .
Based on the data collected, the total number of godwit chicks that became fledging in the Netherlands in 2013 can be estimated at 8900. This estimate is about 37 % higher than for 2011 , but 17 % lower than in 2012. On this basis, it can be argued that the breeding success in 2013 was probably too low to stabilize the population. (see also: vitamin burung)
Rich pastures good for godwit chicks
One of the causes of failure are great for godwits is the lack of food . Godwit chicks eat insects that are found on flowers and herbs in the grass . What more flowery grass , the more food can be found there .
RSPB is campaigning for more 'rich pastures . " Everyone can help by drawing on www.redderijkeweide.nl the petition.