The Drake’s Beach Sanderlings 2021: Bird-a-thon is Back!

The Point Blue Conservation Science Rich Stallcup Bird-a-thon is back, as are the Drake’s Beach Sanderlings! Well, in some ways we never went away, but in 2020 the whole event was transformed into a virtual bird-a-thon with teams going out birding, but the team members birding in different locations due the inability to gather in groups because of COVID-19. Sanderlings members did participate in the event, and birded various sites in the bay area and West Sacramento.

But now that is over (hopefully). Teams will be able to meet again and head out to bird and raise funds for Point Blue Conservation Science.

As a member of the Bird-a-thon Steering Committee, I helped to organize the bird-a-thon and helped to choose the mascot bird this year: the Pine Siskin. We choose this species to highlight for a few reasons. One is that it is a generally underappreciated species. As you can see in the image above, the Pine Siskin is not an obviously flashy bird. But, to quote the new Hansen’s Field Guide to the Birds of the Sierra Nevada when noting that the perched bird can be on the drab side, “Taking flight, however, it changes from somber to eye-catching.” This striking change is due to the yellow patches in wing and tail that are generally concealed when at rest, but which flash dramatically when in flight. A second reason to highlight the Pine Siskin is that this species was hit hard by the salmonella outbreak in California that occurred in the winter and spring of 2021. This disease killed individuals of several finch species, but siskins seemed particularly susceptible. A third reason are the fires burning across California. The Pine Siskin is a finch that breeds in the conifer forests of North America. As such, they have lost a lot of breeding habitat in California this summer with so many fires burning through the conifer forests of the Sierra Nevada.

The 2019 Drake’s Beach Sanderlings team standing on Drake’s Beach in Marin County.

So, in support of the Pine Siskin and the work of Point Blue Conservation Science, the Drake’s Beach Sanderlings are once again asking for your support when we head into the field to race across Marin County to find as many species as we possibly can in one day (September 26, this year). As usual, this will be a face-paced day of blazing from site to site to visit as many habitats as we can and find lots and lots of birds!

This event is a fundraiser for Point Blue, and as such, I ask that if you have the means please donate and support this amazing team of young birders (the longest running youth team that I have ever heard of!), and Point Blue. By donating this cause, you will be supporting climate research that is badly needed, and also supporting and encouraging young birders who represent a hope for the future of our planet that is also badly needed. You can donate by following this link and clicking the ‘donate’ button just to the right of the team photos.

My heart-felt thanks goes out to each person who contributes in support of this amazing cause.

#richstallcup #birdathon #birds #conservation

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Are Humans Evolving?

Are humans still evolving? Have medical advances and the luxuries of modern life removed the pressures that natural selection might exert and so remove the driver for humans to change from generation to generation?

Sketch of the human forearm indicating the median artery (Image Credit: Professor Maciej Henneberg

Several examples can be pointed to which indicate that we humans are still evolving from increasing head size to the reduction in frequency of wisdom teeth. And a new example has just been discovered!

Researchers at Flinders University and the University of Adelaide (both in Adelaide, Australia) have discovered that some adult humans today have three arteries that bring blood to their forearm and hand, while the rest have only two. And the percentage of the population that has three is increasing. These results were published in the Journal of Anatomy in September 2020.

We all had three arteries in our forearms when in utero which are called the ulnar artery, the radial artery, and the median artery. But most adults only have two because the median artery (the one in the middle) generally disappears as a fetus develops. However, sometimes it never disappears, and adults will have a functioning median artery. This variation in development is where the researchers focused their attention.

Anatomists (people who study anatomy) have noted that the median artery disappears sometimes, but not always, for well over a hundred years. Some of these anatomists examined adults born in the 1880s and noted that about 10 percent of them still had their median artery and 90 percent has lost theirs. Researchers from those two universities in Australia mentioned above read these reports and wondered if those numbers had changed. They examined the forearms of adults born in the late 1900s and found that about 30 percent retained their median artery while the percent that lost their median artery was down to 70 percent.

Looking at those numbers, it might not seem very dramatic, but a 20 percent difference over just a few generations is pretty significant in evolutionary terms. If this rate of change continues, everyone born 80 years or more from now will have a median artery as adults. When most people have a median artery as adults, medical standards will need to change. At that point, having a median artery will be the normal condition, and no longer be considered a variant as it is today.

No one is sure why this trait is being favored. Having three arteries that feed the hand does allow for increased blood supply. While it might be tempting to try and explain this change as a reflection of how important hands are to our survival, that idea is not supported by any data. In fact, hands have been important for human survival since before we evolved into humans, so even the idea is a bit weak. Whatever pressures are causing natural selection to favor the retention of a median artery into adulthood is an interesting question that stands open.

This example of the median artery shows that humans are still evolving and that natural selection continues to influence our species even if we don’t understand why it may be occurring.

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