Finches are small passerine birds that are found in many parts of the world. There are over 100 different species of finch, including the Zebra Finch, Gouldian Finch, and House Finch. Finches build cup-shaped nests and lay eggs that hatch after an incubation period. The hatchlings are altricial, meaning they are born without feathers and require care and feeding by the parents. Let’s take a closer look at how finches find mates, build nests, lay eggs, and raise their young.
Finding a Mate
When it comes time to breed, male finches will sing beautiful and complex songs to attract female finches. The males will often gather together in a group, or lek, and perform courtship displays to impress prospective mates. This courtship singing and dancing is a key part of finch reproduction. The females will observe the males and select the most suitable mate. Pair bonding usually occurs each breeding season, as most finches do not mate for life.
Some key factors females consider when choosing a male finch as a mate include:
- Bright plumage coloration – Brighter males tend to be more dominant and healthy
- Complexity of songs – More elaborate songs indicate intelligence and vigor
- Display performance – More active and energetic displays signal good genes
- Nest building skills – Females will observe the male build a practice nest
- Parenting skills – Females may test males by observing their parental care of eggs
Once a female finch has chosen her mate, she will allow him to copulate with her. Finches do not actually have an intromittent organ, so reproduction is achieved through the male mounting the female and pressing his cloaca against hers. This allows the transfer of sperm.
Nest Building
After mating, the pair will cooperate to build a nest in which to lay the eggs. Finches are versatile nest builders, constructing nests in different locations depending on the species. Common nesting sites include:
- Tree branches and forks
- Cavities in trees or walls
- Bushes and dense shrubs
- Eaves and overhangs on buildings
- Nests abandoned by other birds
The male and female finch will collect nesting material such as twigs, stems, leaves and moss. The female does most of the actual nest construction, intricately weaving the materials into a cup shape. She lines the inner cup with soft fibers, feathers, or hair. The small cupped nest provides a cozy space to cradle the eggs.
House Finch Nest
As an example, a typical House Finch nest would be constructed as follows:
- Outer layer – Coarse twigs, stems, strips of bark
- Inner layer – Finer grasses and fibers
- Lining – Hair, soft feathers, plant down
House Finch nests are usually found in nooks or ledges on human-made structures. The nests are about 6 inches wide and 3 inches high when complete.
Zebra Finch Nest
Zebra Finches build very tidy, compact nests out of fine plant fibers. Their nests are spherical with a side entrance hole. Typical materials include:
- Plant stems and fibers from grasses or roots
- Feathers
- Sheep wool
- Human hair
Zebra Finches add material to the nest throughout the breeding cycle to maintain the nesting site.
Egg Laying and Incubation
Once her nest is complete, the female finch is ready to lay her eggs. The typical clutch size is between 3 to 6 eggs for most finch species. The eggs are small, smooth, and oval shaped. Their coloration varies from light blue to white with darker speckles.
The female lays one egg per day until her clutch is complete. She begins incubating the eggs as soon as the first one is laid. Incubation lasts 11 to 14 days before the eggs begin to hatch. Both parents may help keep the eggs warm, but the female spends the most time on the nest. The eggs must be incubated at temperatures between 90 – 104°F to develop properly.
Here are some typical clutch sizes and incubation periods for popular finch species:
Finch Species | Clutch Size | Incubation Period |
---|---|---|
Zebra Finch | 4-6 eggs | 13-14 days |
Society Finch | 4-6 eggs | 13-14 days |
Gouldian Finch | 4-8 eggs | 13-15 days |
House Finch | 3-6 eggs | 12-14 days |
Incubation Behavior
During incubation, the brooding parent will stand horizontally over the eggs to provide warmth and protection. They may turn the eggs periodically as well. The female typically incubates the eggs through the night. The male may take over during the day so the female can forage for food.
If the eggs get too cold during incubation, development ceases. Prolonged chilling can be fatal to the embryo. To prevent this, the parent sitting on the nest is continually warming the eggs with their body and feathers. Blood flow to their belly region increases during incubation as well.
Hatching
When incubation is complete, the finch chicks begin to hatch. They use their egg tooth, a small protuberance on their beak, to pip through the eggshell in a continuous chipping motion. It takes 12-24 hours to fully emerge from their shell.
The hatchlings are altricial – born naked, blind, and helpless. Their eyes are typically closed for the first 7-11 days. They have some light downy feathers but cannot yet thermoregulate their body temperature.
The parents continue brooding the chicks to keep them warm. Within a few days, the chicks open their eyes. At this point, they are more alert but still completely dependent on the parents for food, warmth, and protection.
Finch Chick Development
For the first two weeks after hatching, finch chicks develop rapidly:
- Days 1-5 – Chicks are brooded continuously by parents
- Days 5-7 – Eyes begin to open, quills emerge
- Days 7-10 – Covered in juvenile plumage
- Days 10-14 – Begin leaving the nest briefly
- Day 14 – Fledging age, can fly short distances
The chicks fledge the nest at 14-21 days old. However, they often return to roost in the nest at night for 2-3 more weeks as they gain independence.
Parental Care
Finch parents cooperate to feed and care for the chicks. Crop milk is secreted from the crop lining of both parents to feed newly hatched chicks. Crop milk contains proteins, fats, minerals, and antibodies to help the chicks grow and fight disease.
As the chicks age, the parents forage for seeds, insects, and fruits to bring back to the nest. Nest sanitation is vital so the parents will swallow chick droppings to keep the nest clean.
Both parents feed and brood the chicks. However, the female tends to spend more time at the nest while the male brings food. The parents are very protective and will harass predators or other finches approaching the nest. This parental care continues until the fledglings are independent, usually by 3-4 weeks of age.
Conclusion
This covers the major stages of the finch breeding cycle. Finches utilize courtship displays, intricate nest building, dedicated egg incubation, and bi-parental care to successfully raise multiple broods each season. Their high reproductive rate helps maintain healthy finch populations in the wild.
Observing finch reproduction behaviors and nesting activities can be very rewarding for bird enthusiasts. We see the intricate cooperation between mating pairs, the engineering behind their nests, and the diligence they put into raising each clutch. It is a wonderful glimpse into the avian world.