The New Year certainly did not begin as we all hoped. The devastation of the Marshall Fire was a horrific event that has impacted many BCNA members and friends in the communities of Boulder County. Colorado's Marshall Fire destroyed over 1,000 homes in Marshall, Superior, Louisville, and unincorporated Boulder County, an event that many of us never considered possible. Just over a year ago, the East Troublesome Fire in Grand County jumped over the Continental Divide to threaten the town of Estes Park, something again most thought not possible.
While we all must do what we can to help those directly impacted by the fires in their long journey ahead, this is also a call for all of us to re-evaluate our own lives and our relationship with the natural world and to renew our efforts to mitigate the growing effects of climate change. We must recognize the impact our actions have on climate, and thus, on both our local natural ecosystems and our homes and supporting infrastructure.
BCNA will focus locally to address this challenge through classes and education, through grants for scientific research that pertain to climate change, through volunteer research such as the ecosteward program (see report below), and through advocacy for actions to decrease man's impact on the climate.
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Emergency Notifications
A reminder: you must sign up to get emergency notifications from Boulder County on a cell phone. Cell phone companies do NOT share information with police, fire departments, or sheriff for emergency calls.
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Resilience
The resilience of nature is a lesson and a hope for us all. Ten days after the Marshall Fire, BCNA volunteer raptor monitors reported 19 raptors, more than during an average survey, on the route that includes the fire area. They also saw two prairie dogs in an area that had been burned. And the Northern Saw-whet Owl (above) that is often seen in Louisville has been spotted since the fire.
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BCNA ANNUAL MEETING
WEDNESDAY, FEB 23, 7PM
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The BCNA Annual Meeting and elections to the Board of Directors will once again take place via ZOOM at 7:00 PM on Wednesday, February 23. An invitation to the meeting with the Zoom link will be emailed to all BCNA members the day before the meeting.
This meeting will include an update on significant BCNA news, selection of board members for the coming year, a vote to update the BCNA bylaws (proposed changes), and a report of research grants awarded for the coming year.
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The BCNA Board of Directors has one open at-large position at this time. Please consider applying for this position. We need your ideas and energy to fulfill our mission! Membership will vote on nominations at the upcoming Annual Meeting. |
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GRANT APPLICATIONS
DUE MONDAY, FEB 15
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The Boulder County Nature Association (BCNA) is a private, non-profit membership organization committed to our mission: “Conserve resilient natural ecosystems in our region through science, education, and advocacy.” BCNA is pleased to offer research funding as small one-year grants of up to $4,000 for projects consistent with our mission.
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ECOSTEWARDS: MONITORING AREAS OVER TIME |
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Steve Jones has worked with over a hundred different volunteers over the past 15 years to track breeding bird populations in Boulder County. Many of these volunteers were "ecostewards" or people who volunteer to carefully observe a piece of land over time. Steve summarizes below how he has analyzed the data collected and the changes in breeding bird populations that have been reported. |
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I've looked at data for 70 easily detectable species listed as "rather common," "uncommon," or "rare" on the Boulder County Audubon 2010 Birds of Boulder County checklist. Then I created scatter plots (below) showing the percentage of adopted areas where each species was seen within documented breeding habitat each year. (I'm proud to say I did all of this without ever touching the keyboard or mouse; if anyone would like a demonstration some time, it's easy and exhilarating).
This is a pretty subjective exercise, since the number of areas surveyed each year varies from 9 to 22. To try to address this, I've created two categories:
- All areas sampled during a given year.
- Only those 12 areas that were sampled during at least 10 of the 15 years of the survey.
So here is what a sample graph looks like:
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The preponderance of "increasers" didn't surprise me, since, in addition to urbanization, the primary environmental change driving breeding bird distribution in Boulder County over the past couple of decades appears to have been deciduous tree and shrub expansion throughout the plains and foothills. Many studies have shown that the total volume of vegetation is a strong predictor of breeding bird abundance and diversity. You'll see that most of the species on the "expanding" list nest either in deciduous woodlands or shrublands.
Another factor probably driving range expansions has been ecological succession in and around gravel ponds and reservoirs, which may favor some nesting duck species, along with Bald Eagles, Ospreys, Northern Harriers, and American Bitterns. [Note: I've entered these more rare species on the spreadsheets, but I created scatter plots only for those species that were documented during at least 6 of our 15 years of surveys and that also showed some kind of change over time].
I know, you're wondering about climate change. That's progressing, but 15 years of these kinds of surveys aren't likely to show dramatic changes. For example, I expected to see a decline in the distribution of nesting Dusky Grouse and Red-naped Sapsuckers as a result of aspen die-off, one symptom of global warming. But such a trend just didn't show up on the spreadsheets. It will require more focused observations of these reclusive and uncommon birds over more years to document this anticipated decline.
It's true that some breeding species, including Eastern Phoebe, Black Phoebe, Black-chinned Hummingbird, and Bushtit, have colonized Boulder County from the south during the past two decades. Scholarly articles about these range expansions tend to conclude that while warming temperatures may contribute, the main driving factors are a proliferation of shrubs and deciduous trees in urban and rural areas; and adaptation of cliff-nesting species such as the phoebes to nesting on bridges and underpasses.
Here's my favorite scatter plot of all, showing changes in Ovenbird distribution within areas sampled during at least 10 of 15 years:
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When I look at this image, I think of an exotic flower bursting open. Knowing that Ovenbirds have recently expanded their nesting distribution northward from the scrub-oak woodlands of southern Colorado into the northern Front Range, we might jump to the conclusion that global warming is causing this range expansion. But I think it's useful first to look at the habitats where Ovenbirds are apparently nesting (dense and vegetatively diverse riparian areas in foothills canyons) and ask how those habitats have changed and why.
To my mind, the answer appears straightforward. The shrub and deciduous tree vegetation in these areas is much denser than it was 20 or 30 years ago. That's particularly important for ovenbirds because they need the deciduous leaf litter to build their oven-shaped ground nests. Try building a roofed nest out of pine needles!
So why has this change occurred? Those of you who are relatively new to Boulder County may not know that prior to the 1980s most of our foothills canyons were grazed by cattle. The removal of these cattle and protection of these areas through open space programs helped stimulate the growth and expansion of foothills shrub and riparian woodlands. In a 1998-2013 study of bird populations within the Coal Creek riparian area upstream from Superior that several of us completed in cooperation with Boulder Open Space and Mountain Parks, we documented a doubling of numbers of shrub-nesting and cavity-nesting birds after cattle were fenced out.
It also helped that the 1990s was Boulder's wettest decade on record and this past decade the second wettest. So now we have all these ovenbirds chanting away in these lush canyons, a minor miracle that occurred as a result of a land-use change that many of us hardly took notice of. If you look at the graphs for Black-chinned Hummingbird, Bushtit, Gray Catbird, Yellow-breasted Chat, and Lazuli Bunting, all shrub-nesters, you'll see similar expansions in distribution.
I think we're certain to see climate change playing a stronger role as we continue our observations. This is why I'd hoped that we could carry out this project for at least 30 years. That's about how long it's likely to take before we see these profound long-term changes kicking in. I'll try to complete 5-year compilations from here on out. And if you have to give up your adopted area for any reason, please try hard to find someone to replace you.
I suspect you're also wondering about the rare nesting species that seem to be declining or disappearing locally--including Northern Goshawk, Burrowing Owl, Lewis's Woodpecker, Evening Grosbeak, and Lark Bunting--but that don't show up on the table, below. The problem here is we don't have enough observations in our ecosystem stewardship database to suggest trends. But other databases do. For example, the Indian Peaks Four-Season Bird Counts indicate a steep decline in numbers of Evening Grosbeaks (not to mention cowbirds!). Observations of Lark Buntings by the various local agencies show that while present in Boulder County during the late spring and early summer, these once-abundant grassland-nesters rarely breed successfully here anymore.
So please take these data for what they're worth: one way of looking at changes in Boulder County's diverse breeding bird population. I think our work these past 15 years has been particularly useful in demonstrating how changes in breeding habitats are influencing breeding bird distribution. We're not tracking absolute numbers for sure, but we are tracking distribution, just as the Colorado Breeding Bird Atlas I and II did for the state as a whole.
If we can somehow get in another 15 years of equivalent effort, I think the results will become truly astonishing.
Thanks to all those who have worked on this project for their dedication and patience, Steve
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SUPPORT BOULDER COUNTY NATURE ASSOCIATION |
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A big thank you to all who currently support BCNA! Without your assistance, we would not be able to accomplish all that we do for our community and for the natural world around us. Memberships for the calendar year renew in November and December, but you can renew for next year any time.
Please consider renewing today if you have not already done so.
New members are always welcome!
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