Birds

Spotted Owl. National Park Service.

The old growth forest of Muir Woods represents a fragmented island of the redwood stands that existed 150 years ago. Muir woods is now the last remaining contiguous stand of old growth coast redwoods in Marin County. The abundance of birds and periods of song vary with time of day, season, and weather conditions.

The greatest variety of avian activity occurs during the spring mornings. The most commonly seen include the clever common raven, tiny Pacific wren, blue Steller's jay, and dark-eyed junco. Marin also is home to one of the few stable populations of the old-growth forest dwelling spotted owls, at least some of whom live in Muir Woods and the Mount Tamalpais watershed area. At least 69 bird species occur within Muir Woods, the majority of which are small neotropical migrants such as the Pacific-slope flycatcher, golden-crowned kinglet, and chestnut-backed chickadee.

Old-growth forests - like we have at Muir Woods - offer large and old trees, rich understories, and high amounts of large woody debris. Many bird species rely on this unique habitat and cannot survive in other environments. Ground-cover - such as dense shrubs, mosses, and ferns - help ground-nesting birds to hide their otherwise-exposed nests from predators. In living and dead trees, tree-cavities and deep grooves offer space for cavity-dwelling birds to nest in. This is also good habitat for insects, an essential food source for some species. While many birds rely on old-growth forests, 95% of the original old-growth redwood forests have been cut down for timber. In order to protect these birds, we must protect the old-growth forest habitat that they depend on.

 

Where are all the birds?

Some visitors remark that they saw fewer birds than expected in this kind of forest. There are several explanations for this:

• Time of day: many woodland birds are crepuscular, or most active at dawn and sunset.
• Lack of insects: Redwood trees contain an abundance of tannins, which help them to resist insect infestation and rot. Because of this, there aren’t many insects in the monument and therefore is a limited food supply for insect-eating birds.
• Lack of flowers: The flowering plants in this redwood forest have short and unreliable blooming seasons. More flowers would provide more seeds, nectar, and insects for birds to eat.
• Line of sight: many birds spend their time high in the dense canopy, mostly invisible to the naked eye.

 

Want to watch birds in the woods?

Anyone can observe birds! While equipment like binoculars can be helpful, you don’t need them. Of course, please remember to always stay on trail during your visit to not damage habitat.

To find a bird:

• Look for movement on the ground, in the bushes, high up in the trees, by the creek…
• Be silent and listen to the forest.

Once you see or hear a bird, notice the:

• Location: Is the bird on the ground, high in the canopy, in trees or bushes.
• Colors: What colors do you see on the bird?
• Sounds: What kind of sounds is the bird making? Are they long, short, low, high?
• Behavior: What is the bird doing? Is it jumping from perch to perch, sitting still, travelling with others, or alone?

We thank the many birdwatchers who have contributed their observations to the Park and invite you to also do the same. For local reports on recently spotted birds - and to contribute your own - check out the information about Muir Woods bird sightings on INaturalist, a platform where the public can submit wildlife and plantlife observations.