Swallows are small passerine birds in the family Hirundinidae. There are around 90 species of swallows divided into several genera including Hirundo, Petrochelidon, and Tachycineta. Swallows are found worldwide on all continents except Antarctica. Swallows are aerial insectivores, which means they catch and eat insects while in flight. Swallows build nests out of mud or saliva where they lay their eggs and raise their young. The nest building process is an intricate and time-consuming endeavor for swallows. In this article, we will examine how long it takes different swallow species to build their mud nests.
Nesting Behaviors of Swallows
Swallows are social birds that often nest in large colonies. However, a few species are solitary nesters. Swallows demonstrate high nest site fidelity, meaning they return to the same nesting site year after year. Swallows build two main types of nests:
Mud Nesters
The mud nesters include barn swallows, cliff swallows, and house martins. They construct cup-shaped mud nests on vertical surfaces like cliff faces, building eaves, or cave walls. The mud nesters gather beakfuls of mud and form them into pellets that are layered into a nest. They reinforce the structure with grasses and feathers. Mud nests are very durable and can last for many years.
Saliva Nesters
The saliva nesters include tree swallows and violet-green swallows. They build nests out of thick saliva combined with grasses and feathers. The saliva dries into a hardened gourd-shaped nest. Saliva nests adhere to tree cavities, nest boxes, or cliff crevices. They are more delicate than mud nests.
Nest Construction Timeline
On average, most swallow species take between 1-2 weeks to build a complete nest. However, the total time can vary based on:
- Species – Some species work faster than others
- Clutch size – Larger clutches require bigger nests
- Weather – Cold or wet weather slows progress
- Pair cooperation – Some pairs work together better
- Nest site availability – Competition for sites can delay building
- Predation – Nest failures require restarting construction
Here are estimated timelines for select swallow species:
Barn Swallow
Barn swallows typically take around 1 week to construct a complete nest. The male and female work together gathering over 1000 mud pellets. They lay a foundation of 100-300 pellets first, then build up the walls until the nest is cup shaped. Barn swallow nests are approximately 13 cm wide by 8 cm high.
Cliff Swallow
Cliff swallow nest construction takes 1-2 weeks. The closed, retort-shaped nests are comprised of up to 3000 mud pellets. Cliff swallows nest in very large colonies with up to 6000 nests together. Competition for mud and nest sites may increase build times. Their nest opening is only 5 cm wide.
Tree Swallow
Tree swallows take 1-2 weeks to build a nest depending on the site. Females construct the nest alone out of 700-1500 globs of saliva. Nests in nest boxes can be built faster than natural tree cavity sites. The nest measures 13 cm wide by 8 cm high when complete.
House Martin
House martins build a nest in about 9-12 days. However, a colony may take over a month to construct all nests. House martins nest in colonies averaging 20-40 pairs. Their mud nests consist of up to 1000 pellets and have a 3 cm opening.
Nest Construction Process
Swallow nest building generally follows a predictable sequence over several phases:
Site Selection
The male swallow identifies potential nest sites then shows them to the female. Ideal sites have vertical surfaces protected from the elements. Cliff faces, building eaves, caves, and tree cavities are preferred.
Foundation
Mud nesters: The pair starts laying down the initial mud pellets as the base. They let it dry and harden before adding walls.
Saliva nesters: The female starts the foundation with thick globs of saliva on the cavity surface.
Wall Construction
Mud pellets or saliva globs are added bit by bit to build up the cup-shaped walls. The swallows work from the interior, forming the nest chamber.
Nest Lining
Final nest layers include soft grasses, feathers, and sometimes human-made fibers. These provide insulation and cushioning.
Entrance Tunnel
Mud nesters construct a short entrance tube with final mud reinforcements around the lip. Saliva nests remain open.
Swallow Species | Nest Composition | Estimated Build Time |
---|---|---|
Barn Swallow | Mud pellets | 1 week |
Cliff Swallow | Mud pellets | 1-2 weeks |
Tree Swallow | Saliva globs | 1-2 weeks |
House Martin | Mud pellets | 9-12 days |
Factors That Impact Nest Building
Several factors can influence how long it takes swallows to construct their nests:
Weather
Cold temperatures or heavy rain make gathering mud and insects more challenging. Nest progress may halt during storms. Mud pellets also require adequate drying time between layers.
Predation
Swallow nests are vulnerable to predators like snakes, raccoons, and hawks. Rebuilding a destroyed nest restarts the clock on total construction time.
Pair Cooperation
Pairs that work together seamlessly can construct nests more rapidly. New pairs or uncoordinated efforts slow the pace.
Colony Size
Larger colonies experience more competition for mud collection and nest sites. This can lengthen build timelines.
Nest Site Competition
Availability of suitable nest sites impacts speed. Swallows may get ousted from a site and have to find alternatives.
Clutch Size
Larger clutches require more spacious nest interiors which adds time. Average clutches are 2-7 eggs depending on species.
Conclusion
Most swallow species require 1-2 weeks to complete nest construction. However, factors like weather, predation, nest competition, and pair cooperation can lengthen or shorten timelines. Mud nest builders like barn swallows and house martins may work slightly faster than saliva nesters like tree swallows. But all swallows demonstrate impressive stamina and determination to build secure nests each spring using their specialized methods. Their intricate nests highlight both the urgency of the breeding season and the supreme nest-building capabilities of swallows.