A duck will typically sit on dead eggs for 21 to 28 days before abandoning them.

Ducks instinctively incubate their eggs for the full nesting period, even if the eggs are infertile or the embryos have died. Most duck species sit on eggs for 21 to 28 days, which is the normal incubation period. If the eggs do not hatch by the end of this timeframe, the mother duck will eventually abandon the nest. Some ducks may continue sitting slightly longer, up to 30-35 days, especially in colder weather or if they are young or inexperienced mothers. However, prolonged incubation of dead eggs can be harmful to the duck's health, as she stops eating regularly during this time.

Factors affecting how long a duck sits on dead eggs

• Species: Different duck species have varying incubation periods, ranging from 21 to 30 days
• Weather: Cold temperatures may cause ducks to sit longer, while hot weather can shorten the incubation period
• Experience: First-time mothers may sit longer than experienced ones
• Disturbances: Frequent disturbances near the nest can cause a duck to abandon eggs earlier

Comparison of incubation behaviors in different duck species

Signs that a duck may abandon dead eggs

• Eggs remain unhatched after the normal incubation period
• The mother duck leaves the nest for increasingly longer periods
• Eggs become discolored or develop an odor
• Predators disturb the nest area

What to do if you find a duck sitting on dead eggs

1. Observe from a distance to avoid disturbing the nest
2. If the incubation period has passed, consider removing the eggs to encourage the duck to move on
3. Provide a safe, quiet area away from predators
4. Consult a wildlife expert if you're unsure about intervention

Remember that interfering with wild duck nests may be illegal in some areas. Always prioritize the duck's welfare and natural behaviors when considering any action.