Crissy Field Center wind turbine wildlife impact study

Project Type:  Research
Project Status:  Completed

Crissy Field Center wind turbines

Aerial view of Crissy Field Center with wind turbines

Above: In the Spring of 2012, the Crissy Field Center installed five small-scale vertical wind turbines just northwest of the center in order to generate electricity for its visitors, and serve as a demonstration of urban wind generation for the public. This project aimed to determine if, and to what extent, these turbines affect nearby wildlife populations.

Small scale vertical axis wind turbines have emerged as a developing technology in the renewable energy sector alongside the interest in “urban wind.” More than ever people are looking to generate wind power on a small scale in more urban and developed areas rather than traditional wind farms. They are a growing technology with the capacity to become a fixture in renewable energy generation. In spring 2012, five small-scale vertical wind turbines were placed just northwest of the Crissy Field Center. They demonstrate urban wind generation to the public, and provide the Center with electricity. Small turbines can be an important segment of the renewable energy sector, however it is imperative to ensure that they will not impact our wildlife. Being that they pose a very different threat to wildlife than their horizontal axis counterparts, it is vital that the difference be understood. Thus, a wildlife impact study was completed over the course of a year and a half (July 9, 2012 to December 31, 2013), with the goal of better understanding how this new technology interacts with the environment as a whole, a relationship where there is currently little or no data.

Crissy Field Center wind turbine study areaForster's Terns at Crissy Field
 Above Left: A portion of the survey area around the Crissy Field Center used for the wind turbine study, in which daily morning surveys were conducted.  Above Right: Surveyors searched the survey area for dead or injured birds, bats, or other Crissy Field animals that could have been affected by a turbine strike. Forster's Tern photo by Will Elder, NPS.


In order to determine potential wildlife impacts, a survey was conducted each morning in a designated region surrounding the turbines. The protocol involved walking the area to survey for any dead or injured birds, bats, or other animals potentially affected by the turbines. Any carcasses or observed animals were photographed in place and mapped for location. They were then taken to a wildlife expert to determine to what extent the turbines were involved.

A California Gull was one of two birds found killed by a wind turbine strike at Crissy Field in over a year of surveysStudents at Crissy Field
Above Left: A California Gull, as shown above, was one of only two birds killed by a turbine strike during the study period. The other was a Rock Pigeon. This indicates that the turbines seem to have a minimal effect on bird species, though future research will be needed to confirm such conclusions. Photo by Will Elder, NPS.  Above Right: Though this study suggests that the turbines are minimally dangerous to Crissy Field bird species, we hope others will be inspired to conduct more extensive research on the relationship between vertical axis wind turbines and wildlife populations. Our hope is to learn more about  factors that may contribute to turbine strikes, such as bird type, wind speed or time of day.

Since the study’s completion at the end of 2013, two birds were found to have been killed by a turbine strike. In the beginning of the study, the only victim was a single Rock Pigeon. A second Rock Pigeon carcass was found on site with no external injuries, and was probably not killed by a turbine strike. Only one more bird carcass was found killed in the latter stages of the study--a California Gull. These findings suggest that the wildlife impact for these particular turbines was minimal. Additionally, no migratory birds or endangered species were affected during the length of this study. More research should continue in the future to confirm whether or not our findings apply to other vertical axis wind turbine arrays.

Using the data

While this study provided very interesting and useful information for those who monitor the wind turbines at the Crissy Field Center, the hope is that it will inspire others to begin similar research projects examining the effects of other small vertical axis wind turbine arrays on wildlife populations. We hope to learn more about the likelihood of a bird strike, and if it is dependent on species type, wind speed, time of day, time of year, or a specific turbine. With more information we can begin to understand where it is safe for vertical axis wind turbines to be constructed, thereby allowing us to make predictions about how this developing technology is affecting our world.

Coyote, a potential scavenger of animal carcasses at the Crissy Field CenterA Common Raven, another potential scavenger at the Crissy Field Center
Above: In order to verify our findings, a researcher should place a test carcass (e.g. chicken) within the survey area to see if the carcass will be left for observation the next morning, or scavenged by native wildlife, such as the coyote and raven shown respectively. Photos by Will Elder, NPS.

Detectability/Scavenging Study

In order to determine the value of our data, a future study should include a detectability and scavenging portion. For instance, a lead researcher might randomly place a test carcass (e.g. chicken) within the survey area to see if it is detected by observers, or potentially scavenged prior to morning surveys. This would help us determine if our current survey data is a good reflection of the actual wildlife impacts as they occur.


Great Blue HeronStudent watching birds through a scope
Above: Birds should be identified by an expert bird watcher to determine which species, and how many, are present around the Center, further helping determine if there are certain bird species more impacted by the turbines than others. Great Blue Heron photo by Will Elder, NPS.

Bird Inventory

Additionally, a bird inventory should be completed for the area. This should include a bird expert observing the Crissy Field Center perimeter to note the presence and abundance of different bird species in the area. By completing this inventory, we would hope to understand which bird species are at risk for turbine strikes, and if certain species are at a greater risk than others.


Crissy Field Center Dashboard. Monitor the energy produced and consumed at the Crissy Field Center.

Project contact(s):

Tom Odgers