Tawny eagle eggs can be left unattended for short periods, but not for extended durations. Tawny eagles, like most birds of prey, practice asynchronous hatching, where eggs in a clutch are laid several days apart. This means the first chick to hatch will be significantly larger and stronger than its siblings, able to compete more effectively for food. In cases of scarce resources, younger, weaker chicks may not survive.

Tawny Eagle Incubation Behavior

During incubation, the female tawny eagle will spend the majority of her time on the nest, with the male bringing her food and taking turns incubating the eggs. According to a study of ornate hawk-eagles, a close relative of the tawny eagle, the female incubates about 95-97% of observed hours. In this species, the male will relieve the female for short periods while she feeds, but in Tikal, the male never approached the nest during incubation. This suggests the female tawny eagle will also spend most of her time on the nest during incubation, with the male bringing her food and taking short turns incubating the eggs.

Feeding the Chicks

Image source: Tawny Eagle by Bernard DUPONT

Once the chicks have hatched, the parents will continue to bring food to the nest, with the male delivering prey to the female, who then feeds the chicks. In the case of the ornate hawk-eagle, the male and female may call back and forth for several minutes before exchanging the prey item. This behavior may also be present in tawny eagles.

Exact Duration of Unattended Eggs

The exact length of time that a tawny eagle egg can be left unattended is not specifically documented in the search results. However, based on the behavior of closely related species and the fact that the female spends the majority of her time on the nest during incubation, it is safe to assume that tawny eagle eggs should not be left unattended for extended periods of time.

Factors Affecting Unattended Egg Duration

Several factors can influence the duration a tawny eagle egg can be left unattended:

1. Incubation Stage: Eggs in the early stages of incubation may be more vulnerable to temperature fluctuations and predation when left unattended, compared to eggs closer to hatching.

2. Weather Conditions: Extreme temperatures, heavy rain, or strong winds may require the female to spend more time on the nest to protect the eggs, limiting the time they can be left unattended.

3. Predator Presence: If there is a high risk of predators in the area, the female may be less likely to leave the nest unattended for extended periods.

4. Food Availability: If food is scarce, the male may need to spend more time hunting, leaving the female to incubate the eggs for longer stretches.

Conclusion

In summary, while tawny eagle eggs can be left unattended for short periods, the exact duration is not well-documented. Based on the incubation behavior of closely related species, it is recommended that tawny eagle eggs should not be left unattended for extended periods to ensure their successful hatching and the survival of the chicks.

References

1. Cranes of the World: Black-necked Crane (Grus nigricollis) – UNL Digital Commons
2. Ornate hawk-eagle – Facts, Diet, Habitat & Pictures on Animalia.bio
3. Rise of a Floater Class: Behavioral Adjustments by Breeding Bald Eagles in a Population Approaching Saturation – W&M ScholarWorks
4. Owl Breeding & Reproduction – Owl Pages
5. Tawny Eagle – Birds of the World (birdsoftheworld.org)