Cormorants are unique waterbirds that are often seen perching with their wings spread open after diving. This behavior has led to some confusion about whether cormorants need to dry their wings after swimming and diving. Here we’ll take a closer look at the wettable feathers of cormorants and examine why they spread their wings after diving.
Do cormorants have waterproof feathers?
Many birds have waterproof feathers thanks to special oils that help repel water. Ducks, geese, and other waterfowl have oil glands near their tails that they use to spread water-repelling oil over their feathers. This oil helps trap air within their plumage to keep them dry, buoyant, and insulated in the water.
Cormorants, on the other hand, do not have waterproof feathers. Their feathers get completely soaked when they dive below the surface of the water. Without waterproofing, cormorants would get waterlogged, losing buoyancy and mobility in the water. Their feathers would also take a very long time to dry out.
Why don’t cormorants have waterproof feathers?
Cormorants are pursuit-diving birds that catch fish by swimming and diving underwater. Their wettable feathers help reduce buoyancy, allowing cormorants to swim low in the water and dive more efficiently. The soaked feathers cut down on air trapped within the plumage that would otherwise make them float more. It’s easier for cormorants to chase after fish deeper when they aren’t buoyant like a duck or goose.
Additionally, wet feathers weigh the birds down, making it easier to stay under and propel themselves through the water as they flap their wings. The water weighing down their feathers allows cormorants to reach greater depths as they dive.
How do wet feathers help cormorants swim and dive?
A cormorant’s wettable plumage provides several key benefits that aid swimming and diving:
- Reduced buoyancy – Allows diving to greater depths more easily
- Increased weight – Improves force from wing propulsion underwater
- Reduced resistance – Sleek, wet feathers have less drag than air-filled plumage
- Thermoregulation – Warm blood flowing to the skin transfers core body heat to the cold water
Together, these traits make the cormorant an incredibly efficient diver, specialized for swimming after and catching fish underwater. Their wettable feathers allow them to dive deep, swim fast, and stay under for longer than birds with waterproof plumage.
Do cormorants have to dry their wings?
After prolonged swimming and diving, cormorants will emerge from the water and perch with their wings held outstretched. This behavior has led to the belief that cormorants spread their wings in order to dry them out.
In reality, cormorants do not have to dry their wings after being in the water. Their wet feathers will dry out naturally over time. However, holding their wings open does help speed up the drying process when back on land or perched on a wire.
Why do cormorants spread their wings to dry?
There are several hypotheses for why cormorants spread their wings after diving:
- To dry their feathers faster after being in the water
- To warm up by exposing their undersides to sunlight
- To redistribute waterproofing oils over feathers
- To take a resting posture and relax their muscles
Drying, warming up, and redistributing oils over their feathers are likely the primary reasons cormorants spread their wings. By holding their wings open, they can efficiently dry and preen their feathers to restore waterproofing and insulation for the next dive.
How long does it take cormorants to dry their wings?
Cormorants can dry their wings remarkably fast by spreading them open. In just 20-30 minutes of drying time, most of the moisture will evaporate from their wet feathers.
Factors like air temperature, sunlight, wind, and humidity will affect exact drying rates. Warmer and sunnier weather will speed up drying compared to cool, shady, or damp conditions. Flapping the wings can also help shed water more quickly.
Cormorants spend more time wing-drying after longer, deeper dives that thoroughly soak their plumage. After a quick dip, less drying time may be needed before diving again.
Do other waterbirds spread their wings to dry?
Some other aquatic bird species exhibit wing-spreading behavior for drying and warming up:
- Pelicans
- Anhingas
- Frigatebirds
- Some herons and egrets
However, these species have waterproof feathers so they do not need to dry their wings as urgently as cormorants. Drying the wings is more important for birds with wettable plumage that relies on frequent preening to maintain waterproofing.
Interesting facts about cormorant feathers
- Cormorants have around 25,000 feathers covering their body.
- Their feathers are not waterproof but are excellent at shedding water when flapped.
- Cormorants lack oil producing uropygial glands near the base of their tails.
- Their wettable feathers absorb water and reduce buoyancy for diving.
- Colors range from black, brown, gray, white, tan depending on species.
Cormorant species that spread wings to dry
There are around 40 different species of cormorants and shags. All have wettable feathers and many spread their wings after swimming and diving. Some of the most widespread cormorant species include:
Species | Locations |
---|---|
Great Cormorant | Europe, Asia, Africa |
Double-crested Cormorant | North America |
Pelagic Cormorant | North America – western coasts |
Red-faced Cormorant | Australia, New Zealand |
Guanay Cormorant | South America – western coasts |
All these cormorant species can be observed spreading their wings to dry after fishing and diving.
Conclusion
Cormorants do not have waterproof feathers so their plumage gets soaked during swimming and diving. To help dry out and restore the insulation of their feathers, cormorants will often perch and spread their wings open after prolonged swimming. Drying the wings speeds up evaporation and allows preening to redistribute waterproofing oils. Though not a strict requirement, wing-spreading behavior helps cormorants recover faster for their next dive.