Moskt and Honza (2000) studied the interrelationship between the cuckoo (parasite) and Great reed warbler (host). In their research, ninety nesting sites were observed.
Of the data, 31 nests (34%) were unparasitized, 37 nests (41%) were parasitized only once, and 22 nests (24%) were parasitized numerous times. According to this research, several factors were identified as being most relevant in parasite behavior.
Which of the following identifies the abiotic factor MOST responsible for repeated parasitism?