MO BEAVERS = MO BIRDS!

Saturday June 24^th is the date of the 14^th beaver festival in down Martinez, celebrating the arrival of some uninvited engineers that turned out to be good news for the city ecologically and socially. When the beavers came to Alhambra creek their dam-building produced a cleaner stream, more invertebrates, more fish, more frogs and more birds. Visits from river otter, muskrat and mink became commonplace, and the stream that once dried up every summer became a year round oasis for wildlife. The beavers have since moved on but Martinez remains proud of its role in showing that coexistence is not only possible, but mutually beneficial.

Just this February a study published in Poland found beaver dams not only increase the number of birds over-wintering along the riparian corridor, but in fact boost bird species density and diversity in forests as far as 80 meters away! ”The greater species richness and abundance of both the entire assemblage and certain ecological groups of species in areas modified by beavers suggest that the presence of these animals rearranges the winter distribution of birds at the local scale.”

Join the beaver festival for is a day long celebration of these animals and their dramatic effects on ecosystems and stream health. There is live music, wildlife exhibits, a silent auction and children’s activities. A talented chalk artist highlights the day with a dramatic wildlife mural in the plaza. This year’s festival will focus on beaver role in helping us mitigate the effects of climate change showcasing how their dams reduce fire, combat drought, slow flooding and cool stream temperatures. You might have seen some of the many articles this year describing beavers as climate change superheroes. This is your chance to learn all about why that’s true.

The free festival is in Susana Park in downtown Martinez at the corner of Susana and Estudillo streets from 10:00-3:00. Join us for a dam good time!

MO BEAVERS = MO BIRDS

There was a whopper of a new study published in Europe at last month. It just made it’s way into the journals. It found that in addition to creating wetlands, beaver habitat created bird species diversity in woodlands as far as 60 miles away. That means that our little Martinez science experiment could have changed things in Rosevile, Gilroy or Point Reyes.

The engineering activities of the Eurasian beaver Castor fiber have far-reaching effects on the components of an environment and therefore modify the functioning of the ecosystem. The wetlands thereby created are the most conspicuous effect of beaver activity and attract water-related species. However, there is some evidence suggesting that beavers influence not only aquatic ecosystems but also the terrestrial habitats adjacent to these wetlands and the organisms occurring there.

We found a greater species richness and abundance of wintering birds on beaver sites than on watercourses unmodified by this ecosystem engineer (by 38% and 61%, respectively). Species richness and abundance were higher in the terrestrial habitats near the edges of beaver ponds, but for some species this tendency also held in forests growing at some distance from beaver wetlands. Greater species richness was related to beaver presence, but also increased with a more open canopy and greater forest floor diversity, whereas bird abundance was correlated only with canopy openness. The beaver sites attracted primary cavity nesters, secondary cavity nesters and frugivorous species.

This study provides evidence that the engineering activities of beavers during the growing season have a delayed cascading effect on the richness and abundance of the bird assemblage in terrestrial habitats in winter. This indicates that beaver ecosystem engineering should be seen as having a potential for carry-over effects, in which the consequences of beaver activity become apparent in subsequent seasons. Birds are considered to be ecological indicators, so our results highlight the importance of beavers for the distribution of terrestrial organisms at the local scale, and therefore the functioning of ecosystems beyond the immediate wetland area.

Wowow. That means if a population of beavers changes the diversity and richness of birds along a riparian corridor, those birds also take that diversity and abundance to whatever forest they overwinter in. It’s like putting more dollar coins in circulation: It changes spending patterns in the county where it was launched but also in cities up and down the state and eventually out of the state.

More diverse birds mate with other diverse birds and the entire cycle replicates. And beavers are the launch party.

Number of bird species and individuals

The beaver sites were characterized by a significantly higher number of bird species than the reference sites. The mean number of individuals per 100 m on both transects combined was 5.3 ± 7.4 SD on the beaver sites and 3.3 ± 5.3 SD.

SD refers to standard deviation which just means the amount of distance from the average, So a big SD means there was lots and lots of variability in the numbers and a little SD means that most places they looked did pretty similarly. Beaver sites had MORE bird species than the control sites, and when they looked 100 meters from the site there were still more birds than non beaver sites.

MO BEAVERS = MO BIRDS.

The results of our study indicate that beaver sites are valuable areas for birds wintering in temperate forests. The greater species richness and abundance of both the entire assemblage and certain ecological groups of species in areas modified by beavers suggest that the presence of these animals rearranges the winter distribution of birds at the local scale.

Beavers make a difference to birds around their pond. BUT NOT JUST AROUND THEIR POND. Beavers make a difference to birds SIXTY miles away. That means granting a depredation permit in Rocklin might affect the bird population in Jackson or Santa Rosa.

That means when the fur trade devastated the beaver population it also destroyed bird diversity and species richness at a scale exceeding DDT.

Watercourses transformed by beavers provide valuable wintering sites for a number of bird species and individuals. Bird species richness and abundance in terrestrial habitats adjacent to the water’s edge were correlated with the presence of beaver wetland, but also with characteristics of the vegetation. Terrestrial habitats as far as 80 m away from the beaver wetland still tended to have a greater bird species richness and abundance.

Well okay, sure maybe beavers are good for birds, and fish, and invertebrates and mammals and water but honestly, but they ate my almond tree, so I had to kill them.

BE THANKFUL FOR BEAVERS

heidi08 Beaver ponds, Beavers and Birds November 24, 2022

Happy Thanksgiving beaver heroes! I wish you all a day of family and friends and too much pie except for my Canadian friends who had that already. Had a nice chat about urban beavers with the science editor of the East Bay Times yesterday, so I’m expecting a good article on the horizon. This morning I’ll share this from the Fall Audubon issue sent to me by Laurie in Rocklin.

Beavers and their champions have a lot to be thankful for this year.

GOLDEN GATE AUDUBON PLANS ANOTHER BEAVER FIELD TRIP

heidi08 Attitudes towards beavers, Beavers and Birds September 11, 2022

Good news. Golden Gate Audubon is planning another visit to the Laurel Creek Beavers. September 24th, say do you think it’s in honor of my birthday?

BIRDS AND BEAVERS ON LAUREL CREEK

Beavers are a keystone species, engineering wetland habitats for themselves that also benefits fish, amphibians, and mammals like otters and muskrats. The water, food, and shelter found in beavers’ riparian habitats are among the many benefits to birds (https://goldengateaudubon.org/blog-posts/the-birds-and-the-beavers/).

Beaver dams are known to double the probability of willow flycatchers and the density of song sparrows compared to areas without beavers. The story of the FAIRFIELD BEAVERS (https://baynature.org/2021/11/11/beavers-can-help-californias-environment-but-state-policy-doesnt-help-them/) on Laurel Creek involves the city of Fairfield, which can get a permit to kill beavers, and has removed their dams in the past due to their worries about flooding, but is currently leaving the beavers alone due to the presence of a kit.

First we will watch the beavers near sunrise for about an hour and then bird the creek (about 1 mile long and then back again) that they have dams on. Virginia Holsworth is the admin of the Laurel Creek Beavers Facebook page, and she has led many beaver field trips. She will help us find signs of the beavers (old dams, new dams, slides, chews, etc.) and give the latest updates on these beavers.

We will walk about 2 miles round trip on a mostly flat trail (dirt, partially paved). We will be in a residential neighborhood, so there are no bathrooms or water nearby, and no places to sit. (We suggest visiting a gas station for a bathroom prior to the walk. The nearest public bathroom is at the Laurel Creek Park, which opens at 6 AM, but note that the bathroom stalls do not have doors.)

Participants are asked to be quiet, since we will be meeting early in a residential neighborhood.

This trip is free but advance registration is required. Registration will open two weeks before the trip and close at 4 pm on Thursday, September 22. Directions for registered participants are below.

Directions Final directions will be given a few days before the trip, to the beaver dam location with the most current activity.

Don’t you want to go? It’s already filled with the beaver curious but I’m sure I could talk them into making an extra trip if you’re interested.

AUDUBON LEADS THE WAY FOR BEAVERS

heidi08 Beavers, Beavers and Birds July 24, 2022

Do you remember back before the festival when Elizabeth Winstead wrote that excellent article for Golden Gate Audubon about the Laurel Creek beavers in Fairfield? Well folks were SO excited about this that they wanted a field trip so this weekend Elizabeth and Virginia Holsworth teamed up and gave them the morning they never had before.

Look at these photos and you’ll understand why Audubon matters so much to beavers. Great work ladies!