Colusa County Wildlife Refuge: Northern California’s Hidden Gem

Because I grew up in a small town in Northern California, nature and wildlife have always been a huge part of my day-to-day life. It has been my experience that people in rural areas learn to respect their roots and live in harmony with the Earth, taking care of the land that takes care of them. One of the ways that we are able to do so is through local wildlife reserves. I was fortunate enough to grow up with a wildlife reserve in my backyard. Located only 5 minutes away from my house, the Colusa County Wildlife Refuge (CMR) was the scene of some of my earliest childhood memories and school trips. Though only one part of the Sacramento National Wildlife Refuge Complex, this iconic reserve plays an important role in the lives of many Colusa County residents.

ring-necked duck
A pair of ring-necked ducks, seasonal residents of Colusa County Wildlife Refuge [Source]
Established in 1945, the Colusa CWR currently acts as a safe haven and breeding ground for over 300 types of migratory birds. As Colusa County is extremely agriculturally driven,1 one of the original purposes of the refuge was to prevent bird-inflicted crop damage by providing a habitat for waterfowl and other bird species during their migration season. However, the reserve has become so much more than a crop damage-prevention strategy, and my personal experiences at the refuge have always been positive throughout the years. Every time you visit, you’re guaranteed to see something new. One of my favorite memories is watching waterfowl waddle along the swamps located by the roadside.  This is especially fun when young chicks join the march.

A male California Wigeon, a seasonal resident of Colusa CWR [Source]
Populations at the reserve peak in December2. Some of the most common birds that migrate to this area are mallard ducks, wigeons, and ring-necked ducks3. As the spring months approach, many birds leave to go toward their respective breeding grounds. Water begins to drain from the refuge from June to August, but species such as herons and orioles remain throughout the region during this time period. Then, as the fall season approaches, more birds begin to return again. Some of the first to arrive are Northern Pintails, and their arrival is often used to mark the start of their migration period4.

northern pintails
Northern Pintails, the signalers of migration season in Colusa CWR [Source]
Migrations of these and other species are one of the key features driving population fluctuations in the reserve. A migration can be defined as a periodic movement from one location or climate to another location or climate5. To do so, birds will use methods such as piloting6 (usage of familiar landmarks to return to a specific location) and navigation7 (using various cues to determine one’s position in reference to a goal). There are many factors that determine when birds migrate towards and away from the Colusa CWR throughout the year. Decisions to migrate can be triggered by different cues such as changes in food availability, temperature, and day lengths. One of the main drivers is access to resources, primarily food and space. Abundant resources mean that less energy needs to be allocated to feeding, which is why birds often leave an area once supplies run out. Since the Colusa County Wildlife Reserve tends to dry up during the summer and food resources become scarce, there are typically fewer birds in the area.

I’ve recently learned that this seasonal variation in transient bird populations at the reserve drastically affected my initial impression. The first time I visited, the reserve was quite barren and dry, with few birds in view. However, when I visited later in the year, there was drastically more wildlife. Different species of birds could be spotted left and right, and there seemed to be something different at every turn of the path. I also found that these trails, which allow people to tour the refuge, are one of the best features of the Colusa CWR. There are both roads and walking paths that allow individuals to better educate themselves on the history of the reserve, and learn about those who claim the refuge as home. Audio tapes are also available. Speaking personally, these greatly enhance the visitor experience. Furthermore, all of the elementary schools in Colusa County visit the reserve at some point every year. This was actually how I was introduced to the refuge. Learning more about the refuge has inspired me to learn more about environmental law, as well as the policies that are behind establishing these safe havens for birds. For those located in Northern California and interested in wildlife, I would definitely recommend a visit to the Colusa County Wildlife Refuge. Located an hour north of Sacramento, and just outside the historic town of Colusa, the Colusa CWR is definitely a place worth visiting.

Simran Grewal is a 3rd year undergraduate at UC Davis studying Neurobiology, Physiology, and Behavior. In her free time, she enjoys biking, playing basketball, and being involved in student government.


1 “Plan Your Visit – Colusa – U.S. Fish and Wildlife Service.” U.S. Fish & Wildlife Service,

2Seasons of Wildlife – Colusa – U.S. Fish and Wildlife Service. (n.d.). Retrieved March 29, 2018, from

3 “Plan Your Visit – Colusa – U.S. Fish and Wildlife Service.” U.S. Fish & Wildlife Service,

4 “Plan Your Visit – Colusa – U.S. Fish and Wildlife Service.” U.S. Fish & Wildlife Service,

5Alerstam, T., & Lindström, Å. (1990). Optimal bird migration: the relative importance of time, energy, and safety. In Bird migration (pp. 331-351). Springer, Berlin, Heidelberg.

6Nevitt, Gabrielle. “Topics 6 & 7 :Biological Timekeeping and Introduction to Migration, Orientation and Navigation.” NPB 102 . NPB 102 , Davis, Kleiber Hall.

7Nevitt, Gabrielle. “Topics 6 & 7 :Biological Timekeeping and Introduction to Migration, Orientation and Navigation.” NPB 102 . NPB 102 , Davis, Kleiber Hall.

Featured image: A Great Blue Heron (Ardea herodias occidentalis) [Source]


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s