Inca doves are small, ground-dwelling doves found in the southwestern United States and Mexico. They build simple nests on the ground or in bushes, trees, and cacti. Inca doves prefer to nest in areas with short grasses or sparse shrubs that provide cover while allowing them to easily spot predators. Their nesting habits and preferred nesting locations allow us to better understand their biology and ecology.
Nesting on the Ground
Inca doves often build nests directly on the bare ground. This is likely an adaptation to their open, arid habitats which lack many trees or dense vegetation for elevated nest sites. Ground nests are usually a simple scrape in the dirt lined with twigs, grass, and feathers. The eggs and chicks are well-camouflaged against the ground but rely on the parents for vigilance against ground predators.
Some key facts about Inca dove ground nests:
- Located in open areas with low vegetation like grasslands, deserts, farms, and backyards.
- Scrape or shallow depression in bare dirt.
- Lined with fine grasses, twigs, and feathers.
- Typically 2 white eggs are laid.
- Eggs and chicks rely on camouflage to avoid detection.
- Adults keep watch and can perform distraction displays to protect the nest.
Ground nests have the advantage of being simple to construct in open habitat. However, they are vulnerable to many predators like snakes, rodents, and ants. The adult doves aggressively defend against threats. But frequent disturbance often leads them to abandon the nest. Ground nesting limits where Inca doves can breed to areas with low predation pressure.
Nesting in Shrubs and Trees
Though ground nesting is most common, Inca doves will also build nests elevated in trees, shrubs, yucca, and cacti. This provides greater protection from terrestrial predators. Tree and shrub nests are flimsy platforms of twigs and grass placed on a horizontal branch. Prickly pear and cholla cactus are also used when available. The nests are very small and shallow due to the dove’s tiny body size.
Some key facts about Inca dove elevated nests:
- Typically 3-10 feet above ground.
- More protected from terrestrial predators.
- Cacti nests provide protection via spines.
- Shallow platform of twigs and grass built on branches.
- Prone to overheating without shade.
- Sometimes usurped by other bird species.
Elevated nests provide more cover and may have higher reproductive success. But shrubs and small trees are relatively scarce across the arid Inca dove habitat range. Competition from other birds can also make elevated sites hard to acquire. Still, nesting above ground allows the doves to exploit resources away from dense predator populations on the desert floor.
Adaptations for Hot, Open Nests
Whether on the ground or elevated, Inca dove nests are exposed and vulnerable to temperature extremes. However, the doves have behavioral and physical adaptations to protect the eggs and chicks:
- Nest in shade when available to reduce sun exposure.
- Build nests with insulating materials like grass and feathers.
- Rotate sitting tightly on eggs to provide warmth and shade.
- Dove body heat warms eggs efficiently due to small body size.
- Eggshells are thin but heavily pigmented to reduce solar heat gain.
- Light egg color reflects more radiant heat than dark colors.
- Chicks can thermoregulate early to reduce parental attendance.
Thanks to these adaptations, Inca doves can successfully breed across hot desert environments. Their resilience allows them to nest in sites vulnerable to extreme temperatures. This flexibility helps the species thrive across its range despite the challenges of desert nesting.
Ideal Nesting Conditions
Even though they are highly adaptable, Inca doves prefer nesting sites that provide:
- Open areas with good visibility to spot predators
- Sparse ground cover so chicks can move easily
- Shallow depressions or vegetation to partially conceal the nest
- Some shade to reduce temperature extremes
- Elevated sites more protected from ground predators
- Good drainage during rains to avoid flooding
- Nearby food and water sources
Locations that meet these criteria will have the highest nest success and number of broods raised in a season. Even though the doves are not picky nesters, they still thrive best in certain habitats. Understanding features that lead to optimal nesting can help guide conservation efforts in areas where Inca dove populations are threatened.
Timing of Nesting
Inca doves can breed nearly year-round if conditions allow. However, most nesting activity peaks in the spring and summer months. The timing varies across their range:
- Arizona: March through September, with a peak from May to July
- California: April through August, with a peak in June
- Texas: March through August with peaks in April and June
- Mexico: February through October, peaking April to June
Nesting is timed to coincide with periods of highest food availability, especially seeds and insects. It also ensures chicks fledge before the hottest and driest conditions of late summer. Inca doves rarely nest during mid-winter due to harsh weather and scarce resources.
The length of the nesting season enables the doves to produce multiple broods per year. Each breeding pair can raise around 2-6 broods in a season. This high reproductive potential is key to sustaining Inca dove populations.
Nest Construction
Building the nest is done primarily by the male dove over 2-4 days. The steps include:
- Scrape out a shallow bowl in dirt or flatten shrubbery
- Line bowl with fine grasses and twigs
- Add soft lining of feathers last
- Reinforce nest walls with debris
- Shape into compact shallow cup around 2 inches deep
The female may contribute some materials but does not construct. The male defends the nest site while building. Nest sizes average 4 inches across and 2 inches deep to hold a clutch of two eggs.
Egg Laying and Incubation
Once the nest is complete, the female lays a clutch of two white eggs. The eggs are oval, smooth, and glossy. Size averages 0.8 inches long and 0.6 inches wide. Eggs are laid at around dawn every other day until the clutch is complete.
Incubation begins immediately with both sexes sharing duties. Sharing allows near constant incubation and reduces risk of overheating the eggs. Incubation lasts 11 to 14 days before the altricial chicks hatch. The chicks are blind and mostly naked.
Both parents feed and brood the chicks. Chicks grow quickly and leave the nest at 12 to 15 days old. They remain dependent on the parents for several more weeks. Parents may reuse the same nest for multiple broods in a season.
Threats to Nests
Inca dove nests face many natural threats across their range:
- Ground predators like coyotes, foxes, skunks
- Snakes – gopher, bull, rattlesnakes
- Other birds stealing nest sites
- Ants and other insects
- Overheating eggs and chicks
- Weather like hail, floods, wind
- Habitat loss from development or agriculture
- Nest disturbance from livestock or humans
The most common cause of nest failure is predation, especially by ground snakes. Parental vigilance offers some protection. But repeated threats often lead to abandonment. Human activities like construction, farming, and recreation can also impact local nest success rates.
However, Inca doves persist despite these challenges. Their resilience stems from high reproductive rates and flexibility in nest site selection. These adaptations enable the species to thrive across diverse and often harsh environments.
Conclusion
In summary, Inca doves build simple nests on the ground or elevated in vegetation. Ground nesting provides ease of construction in their open habitats, while elevation offers more protection. Their nests are vulnerable to extreme heat and weather. But adaptations like egg color, nest materials, and parental care aid chick survival. Timing, location, and habitat resources are key factors influencing nest success rates. While threats exist, the dove’s adaptive nesting behavior enables thriving populations across the Southwest.
