Towhees are small songbirds found throughout North America. There are three main species of towhees: the Eastern Towhee, the Spotted Towhee, and the Canyon Towhee. Towhees build nests on the ground or in low bushes and lay 3-5 eggs per clutch. The eggs hatch after about 12-14 days of incubation. Once the chicks hatch, both parents work together to feed and care for them until they are ready to leave the nest, or fledge. So how long does it take for towhee chicks to grow and develop enough to fledge?
Incubation Period
The incubation period, or the time it takes for the eggs to hatch, is approximately 12-14 days for towhees. The female towhee does most of the incubating while the male brings food to her. She will leave the nest for short periods to forage and stretch her wings. Throughout this 2 week period, the parents must keep the eggs at the proper temperature and humidity levels for normal embryonic development to occur.
Nestling Stage
Once the chicks have hatched, they enter the nestling stage where they are completely dependent on their parents for food and warmth. At hatching, towhee chicks are altricial, which means they are born naked, blind, and helpless. Their eyes begin to open around 5 days after hatching. Feather tracts start to emerge around 3 days old and pinfeathers around 6-7 days old.
During this nestling period, both parent towhees feed the chicks repeatedly, mainly with insects and arthropods. The chicks grow very quickly, increasing their weight up to 10 times from hatching to fledging! Proper nutrition is critical during this rapid growth phase. The nestling phase lasts approximately 9-12 days in towhees.
Fledgling Stage
The fledgling stage begins once the chicks leave the nest, which occurs between 9-13 days after hatching. So in total, it takes towhee chicks about 3 weeks (21-27 days) from hatching to fledging. Fledglings are still unable to fly well at this point. Their flight feathers are only partly grown in and their tails are short. The parents continue to feed and protect the fledglings on the ground over the next couple weeks until they become independent, which occurs around 4-5 weeks after hatching.
Here is a table summarizing the developmental timeline for towhees from egg to independence:
Stage | Duration |
---|---|
Incubation | 12-14 days |
Nestling | 9-12 days |
Fledgling (pre-independence) | 2-3 weeks |
Independent Juvenile | Around 35 days after hatching |
Factors Affecting Fledging Time
While the average fledging period is about 3 weeks, there are some factors that can influence how quickly towhee chicks develop and leave the nest:
Number of Chicks
When there are fewer chicks in a brood, each chick may be fed more frequently and grow faster. With larger broods, competition for food is greater and chicks often fledge at the slower end of the range.
Weather
Cold temperatures or severe storms can sometimes delay fledging since the chicks need extra time to grow flight feathers. However, in very hot weather chicks may fledge sooner to escape overheating in the nest.
Availability of Food
Plentiful food enables faster chick development and earlier fledging. When insects and other prey are scarce, chick growth is stunted which delays feather growth and fledging date.
Nest Predators
If predators are spotted around the nest, towhee parents may encourage fledging earlier than normal to protect the chicks.
Geographic Location
In warmer southern regions, towhee chicks may develop a bit faster than in cooler northern areas.
Fledgling Care and Survival
The first few weeks after leaving the nest are the most dangerous for fledgling towhees. Even after they become better fliers around 3-4 weeks old, juveniles still depend on their parents for another 1-2 weeks as they learn to effectively forage on their own. The parents continues bringing food to them and warning them of any potential dangers.
Hazards fledglings face include predators, lack of food, collisions with manmade objects, and extreme weather. Nearly 70% of fledgling mortality occurs within the first few weeks outside the nest. However, towhees that successfully make it to adulthood typically have an average lifespan of 2-3 years in the wild.
Conclusion
In summary, towhees take around 21-27 days from hatching to fledging, with an incubation period of 12-14 days and a 9-13 day nestling stage. The exact fledging age depends on various factors like brood size, weather, and location. Proper feeding and parental care are essential to ensure fledglings survive past independence. With attentive parenting and adequate food resources, most towhee chicks will fledge close to 3 weeks after hatching.