Throughout the Anthropocene, urbanization has changed the environment for birds, modifying the types and abundance of available materials to build their nests. Discarded plastics and other anthropogenic materials are very abundant in urbanized and agricultural areas and are being used by birds to build nests, constituting a potential threat to them. Objective: To evaluate the materials used for several species of birds living in an urbanized environment. Methods: We evaluated the composition of 20 nests of several species of birds found in the campus of Universidad Nacional. Results: 52.6% of nests contained some sort of waste classified in 13 types of anthropogenic materials, where the most common were wool, strings and thread. The species with the highest percentage of nest weight comprised by anthropogenic material was Campylorhynchus rufinucha Conclusions: Our results demonstrates the widespread use of anthropogenic waste as nesting material.
Philoponella vicina O. Pickard-Cambridge 1899 rests on its orb web in a cryptic posture with its legs folded against its body. While feeding, the spider coats the entire prey with digestive fluid and changes its posture, spreading its anterior legs wide. We tested whether this change in leg position may function to protect against damage to its legs from its own digestive fluid. When we touched detached legs I with prey packages wetted with digestive fluid, more setae fell from the legs than when we applied tap water in a similar manner. In addition, intersegmental membranes were damaged by digestive fluid, but not by water. This and other uloborids may thus break their cryptic postures while feeding in order to avoid damage from their own digestive enzymes.
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