Colorado Birding Challenge

The 2026 Challenge will be held on Saturday, September 5.

Registration is now open!

The county birding event of the year!

Have fun birding the Colorado county of your choice this fall and help raise funds for CFO and our conservation initiatives. There are lots of ways to participate and see how many species you can find in 24 hours!

HOW TO PARTICIPATE

The idea for the COBC is based on other large, state-based birdathons like New Jersey’s World Series of Birding and The Great Texas Birding Classic. People form birding teams to see how many different species they can find in 24 hours according to the ABA Big Day Rules. Donations from friends and family, often in the form of a pledged amount for each species the team can find, help CFO generate funds needed for its programs and conservation initiatives.

There are five categories depending on how much time and effort you want to put into the 2026 COBC.

The Challenge. The most competitive category, teams of two or more go all out to find as many species as they can within their chosen Colorado county.

The Under-25 Challenge. As the name implies, teams must be made up of individuals aged 25 years or younger, although an adult may accompany them for supervision and/or transportation.

The Green Challenge. This category is for those who want to minimize their carbon footprint by using only self-propelled (non-motorized) transportation (walking, pedaling, paddling, etc.).

The Big Sit. Choose one location for your effort and record all birds you can positively identify from there. This could be your yard, your go-to local birding hotspot or the top of Mount Audubon!

Bird Your Own Way. For everyone else there’s BYOW! You can participate on your own, host a birding party, do a “Big Sit” in your yard or favorite hot spot or any other plan that strikes your fancy.

HOW TO COMPETE

The COBC has a county birding focus designed to keep the territory covered to a reasonable level and make more time for birding. People across the state can participate locally, applying their knowledge of local birding. Alternatively, people can elect to bird in a county that offers something different from their local birding. With 64 counties in the state, there’s something for everyone!

But wait, isn’t there a wide variety of habitats between the counties? How can teams compete fairly when some counties have more species than others? This is where the idea of County Par comes into play. To even the playing field, we used eBird data for each county over the past decade to determine the maximum number of species one might expect to find in each county in early September. The differences are quite dramatic, with the highest par being assigned to Larimer County (109) and the lowest to Gilpin and Mineral Counties (51). The team that can find the highest percentage of the county par value will be the winner.

PRIZES FOR THE WINNING TEAMS

In 2026, we have two presenting sponsors: Swarovski Optik and Front Range Birding & Optics. Swarovski will award a prize package to the winners of The Challenge category and will donate $2.00 for every bird found by all the COBC teams combined! Front Range Birding will provide prizes – details to come!

This provides even more excitement and motivation for teams to maximize their county birding totals!

USING EBIRD TO RECORD YOUR SIGHTINGS

Teams must submit an eBird Trip Report as the official tally for all birds counted on the day. We encourage teams to keep individual eBird checklists for each location visited rather than keeping long traveling lists that are of limited value to researchers. Trip Reports must be emailed to cobc@cobirds.org along with your team’s name and county by 5 PM on Sunday, Sept. 6.

County Par Map

Looking for a competitive advantage?

Choose to bird in a county that has not yet been selected.

Can't join in person but want to support a team?