If you take photos of purple things you may have noticed that your camera renders the images as blue.
My classic example is the purple honeycreeper photo which I used on the blog in 2014. The bird looks blue in the photo above but in the photo below, taken with a different camera or edited differently, the bird is purple. The field guide says he is deep violet-blue, thus named the purple honeycreeper.
The purple-turns-blue problem is caused by the fundamental difference between how our eyes see violet light and how a camera does.
Digital cameras distinguish colors in about the same way as the human eye. Most likely however, distinguishing colors at the blue [violet] end of the spectrum utilizes the blue and green sensors rather than the blue and red sensors used in humans.
p.s. Light is violet. Purple is a color constructed by our brains. Bird brains see the color purple differently than we do because they can see ultraviolet light. I’m sure the purple honeycreeper looks quite different to his fellow birds. Perhaps he is ultraviolet.
When I wrote on Tuesday about non-functional grass in Las Vegas, several of you remarked on the Valley’s many golf courses that use so much water. Should they be considered non-functional grass?
Since I’m a birder and not a golfer I would view golf courses as “non-functional” except that some are very good for birds. Courses managed for low chemical use, clean water, and interspersed wildlife habitat are great for birds, especially when their location is an oasis in the midst of other land uses. Courses can achieve these goals and be recognized for their efforts through the Audubon Cooperative Sanctuary Program for Golf Courses.
The Bob O’Connor Golf Course in Schenley Park, affectionately known as The Bob, is just such an oasis. Audubon certified since 2012, the course is savanna habitat interspersed with thickets and bordered by forest and residential neighborhoods.
I see birds at The Bob that are hard to find elsewhere including nesting orchard orioles, barn and tree swallows following the mowers, and merlins in winter.
When I walked around (pond-sized) Panther Hollow Lake in Schenley Park last Friday, I had to dodge high water. On Saturday I expected to see the same water level, or even higher, but it had dropped significantly. Panther Hollow Lake is doing its job.
Panther Hollow Lake has a smart valve governed by the solar-powered weather instrument in the photo below. The smart valve knows the weather forecast and closes during heavy rain events to hold back fresh water that otherwise flows into Pittsburgh’s combined sewer system. After the danger has passed and before the next storm the valve slowly releases water to provide room in the lake for the next downpour. Thus Panther Hollow Lake prevents downstream flooding in The Run neighborhood.
At normal water level three concrete steps edging the pond are exposed. On Friday 13 August all but the top step were hidden (above) and some walkways were flooded (below).
When I returned 24 hours later the water was lower and all three steps were exposed. Here are the same three scenes on Saturday 14 August.
Today’s forecast calls for thunderstorms with potentially heavy rain. Panther Hollow Lake is ready. The smart valve is doing its job.
Birds don’t have this problem. If the loss is in their inner ear, their bodies repair the damage. Learn more in this vintage article: Birds Can Recover Lost Hearing.
Perhaps birds can recover their hearing because their lives depend on it. Gene Henderson reminded me of a high-pitched danger call that American robins make. At 7200 to 8400 Hertz it’s now outside my hearing range. Can you hear the four calls in the recording below at 2,5,8 and 11 seconds? They look like checkmarks on the sonogram.
Cornell’s cicada hypothesis is based on data from the National Wildlife Health Center and the consortium of wildlife agencies investigating the mysterious deaths, summarized here from the Ithaca Times article:
The illness appeared about a week after the Brood X cicadas emerged in mid-May.
The geographic distribution of the illness matches the Brood X map, including its non-contiguous nature, yellow on the map below.
The illness did not spread to nearby states that did not have Brood X cicadas.
The illness waned as the cicadas died off and dropped precipitously after the cicadas disappeared.
This is great news for western Pennsylvania. We do not have Brood X cicadas, instead we have Broods V and VIII, the last of which appeared in the Pittsburgh area as Brood VIII in 2019. It will be 12 to 15 years before they re-emerge: Brood V in 2033 and Brood VIII in 2036. If the problem was caused by magicicadas we’re off the hook in Pittsburgh for a very long time.
Nature doesn’t follow state lines and political boundaries but state agencies have to. Thus all of Pennsylvania was told to stop feeding birds until scientists learned more about the mysterious bird deaths. Scientists are getting close to an answer and soon (I hope!) we’ll be able to feed birds again.
In summer, folks in western Pennsylvania and northern Ohio flock to Lake Erie‘s shore to beat the heat. The water provides a respite but in July the western end is hotter than anywhere else in the Great Lakes. That’s because Lake Erie is shallow and shallow water is quick to take on the temperature of the surrounding air. So how shallow is Lake Erie?
Lake Erie is the fourth in line of the five Great Lakes and happens to be fourth largest by surface area — 9,940 square miles.
But as you can see in this bathymetric map it is also the shallowest (blue is deep, red is shallow). Lake Erie’s average depth is only 62 feet with the deepest spot just 210 feet near Long Point, Ontario.
It’s easier to see how shallow it is in this diagram from Michigan Sea Grant. Even Lake Ontario, the smallest by surface area, is 3.8 times deeper! (Lakes Michigan and Huron are superimposed on each other because they have the same pool level, 577 feet above sea level. Click here to see the complete diagram.)
Since the shallowest water is first to heat and first to freeze, the surface temperatures roughly match the lake depths. As of yesterday, 13 July 2021, the water at the western end of Lake Erie was close to 80 degrees F.
Symptoms of the illness include a discharge and/or crusting around the eyes, eye lesions, and/or neurologic signs such as falling over or head tremors. Infected birds always die. Scientists are investigating but still don’t know what’s causing it.
The disease has been reported in 27 Pennsylvania counties in these species: blue jays, European starlings, common grackles, American robins, northern cardinals, house finches, house sparrows, eastern bluebirds, red-bellied woodpeckers, Carolina chickadees, and Carolina wrens. Tri-State Bird Rescue and Research in Newark, DE has found that the disease primarily affects fledgling European starlings, blue jays, and common grackles.
Cease feeding birds and providing water in bird baths until this wildlife mortality event has concluded to prevent potential spread between birds and to other wildlife.
Clean feeders and bird baths with a 10% bleach solution.
Avoid handling dead or injured wild birds. Wear disposable gloves if it’s necessary to handle a bird.
Keep pets away from sick or dead birds as a standard precaution.
To dispose of dead birds, place them in a sealable plastic bag and discard with household trash. This will prevent disease transmission to other birds and wildlife.
To underscore the point, Audubon Nature Stores will discontinue the sale of seed and bird feeders for the time being.
Do your part. Stop feeding birds until this wildlife crisis is over.
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UPDATE, 2 July 2021: The mysterious illness has now been reported in DC + eight states: VA, WV, MD, PA, DE, IN, OH, KY and more closely matches the Brood X cicada map though this may be a coincidence. My revised attempt at mapping the bird death hotspots, below, is just a rough idea not the whole story. i.e. Do not rely on my map!
UPDATE from PA Game Commission, 8 July 2021 (posted here on 21 July): As of 8 July 2021 Wildlife Futures received 1,525 reports of dead birds in Pennsylvania. Roughly 25-30% (approximately 500) are likely associated with the current songbird mortality event. To date, the morbidity/mortality event appears to be targeting fledgling common grackles, blue jays, European starlings, and American robins. So far the following pathogens have been ruled out: Salmonella, Chlamydia, avian influenza virus, West Nile virus, Newcastle disease virus, herpesviruses, poxviruses, and Trichomonas parasite.
(photo from NPS via DNREC, maps from Wikimedia Commons. Click on the captions to see the originals)