Investigation on the effect of location on bird’s nest predation Abstract:
Nest predation impacts the success of avian species. To test if the location of the nest impacted upon the amount and time the nest was predated upon, artificial nests with plastiscine eggs were placed in exposed and protected environments for two weeks in the greater Sydney region. It was hypothesized that those nests in exposed environments will be preyed upon more and in a shorter period of time then nests in a protected environment. It was found that nests in an exposed environment were predation upon significantly more (X² = 17.38, d.f.=1, critical value=3.84 p<0.05) than nests in a protected environment. A significant association was also found in the amount of time until the nest was attacked and the location of the nests. (t=2.15, degrees of freedom=85, probability>5% therefore Ho is rejected) the results show that nests in exposed environments were attacked in a in a shorter space of time compared to the nests in protected environments. Introduction:
The largest contribution to lack of nesting success in avian communities (Wiens 1989) and is said to be predation, and is thought to influence location of avian nest locations and reproduction. (Bosque and Bosque 1995) Predators are animals that rely on other animals as a source of nutrition. In an attempt of protecting nests and avian individuals from being attacked camouflage is used as a form of defense. For example, the nest being off the ground if not a ratite reduces predation from specific species such as dingoes as they are unable to reach the nest. Camouflage helps reduce predation from animals with poor eye sight such as snakes. However, for predators to survive, they are forced to evolve (adapt) to defensive mechanisms. (Knox 2010) To discover if the different habitats relate to different amount of predation, and the time of until predation occurs an experiment needs to be done. This study investigates whether artificial nests in an exposed environment will experience the same amount of predation and in the same amount of time until attacked as nests in protected environments. It is hypothesized that nests in exposed environments will be preyed upon more and in a shorter period of time then nests in a protected environment. Method:
To determine which nests, exposed or hidden would be attacked and times that the nest was attacked, an artificial nest predation experiment was used, determining whether or not nest location will affect the amount and time of predation to the nest. The experiment was conducted in March 2011 throughout the suburban coastal area of Wollongong. The artificial bird’s nests were constructed by cutting a tennis ball in half, then using craft glue to stick coconut bark on and around the two halves and let the two halves set. To make the artificial eggs, use plasticine and roll in the palm of your hands until a small bird’s egg shape is achieved that is approximate 2 cm in height. One of the two artificial nests is to be placed in an exposed environment in the costal suburban area of Wollongong; the other is to be placed in a hidden environment. Exposed: an exposed environment is an area in which the nest can be clearly seen for example a tree which have lost a lot or don’t have much foliage. Protected: a hidden environment is an area in which the artificial nest cannot be easily found (camouflaged) such as in thick foliaged plants like bushes, The nests need to be checked every 2 days to see if they have been attacked, observe and record any signs of attack. Such as damage to plasticine eggs, eggs missing completely, nest damage or nest missing completely. This experiment is to be repeated 42 times. To determine the predator which attacked the bird’s nest, compare the markings on the attacked plasticine eggs to animal skulls. After the information was recorded, a T-test was used to test the null hypothesis “artificial nests that are in an exposed...
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