Nest construction by a ground-nesting bird represents a potential trade-off between egg crypticity and...

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Predation and thermoregulation pose significant challenges for ground-nesting birds.
• Nest characteristics influence both predator avoidance (crypticity) and egg temperature regulation.

Purpose of the Study:

• To investigate the trade-off between nest crypticity and thermoregulation in piping plover (Charadrius melodus) nest construction.
• To determine if pebble selection by piping plovers serves dual functions of camouflage and thermal regulation.

Main Methods:

• Observational study of piping plover nest site selection and pebble characteristics.
• Color analysis of selected pebbles versus randomly available pebbles.
• Experimental manipulation using artificial nests to assess thermal properties and predation risk.
• Thermal modeling to predict nest temperatures under various conditions.

Main Results:

• Piping plovers selected whiter pebbles that matched egg coloration, suggesting a crypsis function.
• Nests with higher contrast to the substrate faced greater predation risk.
• Selected pebbles exhibited higher near-infrared reflectance, indicating a thermoregulatory function.
• Artificial nests with selected pebbles remained cooler than those with random pebbles, with temperatures up to 2-6°C lower.

Conclusions:

• Pebble selection by piping plovers demonstrates a trade-off between visual crypsis and thermal regulation.
• Light-colored, thermally reflective nest materials may be an adaptive strategy for ground-nesting birds facing predation and heat stress.
• Nest construction behavior can play a crucial role in maintaining optimal egg microclimates.