[Tweeters] Stop Window Strikes

Christine Southwick clsouth at u.washington.edu
Fri May 27 13:48:05 PDT 2016


Yesterday I saw the square decals at my local Fred Meyer next to the birdseed. Didn't notice the price as I was in a "grab the seeds and pay mode".

Christine Southwick
N Seattle/Shoeline
clsouthwick at q.com



On Fri, 27 May 2016, Neil Johannsen wrote:


> Date: Fri, 27 May 2016 12:22:08 -0700

> From: Neil Johannsen <neil.johannsen at gmail.com>

> To: tweeters at u.washington.edu

> Subject: [Tweeters] Stop Window Strikes

>

> Bird Lovers:

>

> An estimated 100 million birds die each year from window strikes. Most of us have experienced the heart-breaking thud sound, or found dead birds below our windows.

>

> The death of a beautiful Golden-crown Sparrow set me hunting for the best solution a week ago - to end the carnage.

>

> For the sake of others in our group,I found this: windowalert.com. It’s a product from Bend. Oregon. I have no financial relationship with this company; i simply want to

> save bird lives.

>

> What I learned:

>

> Birds can see certain light frequencies--including ultraviolet--that humans cannot see.

>

> In fact, many songbirds have feathers that reflect ultraviolet light. This light is used to communicate species, gender, and perhaps even social standing. Birds can see

> this ultraviolet light under normal, daylight conditions. Humans require the assistance of a black light.

>

> Why?

>

> 1) Both birds and humans have photoreceptive 'cones' in the retina located at the back of the eye. These cones allow us to see color light. The human eye contains 10,000

> cones per square millimeter. Songbirds, for example, have up to 12 times this amount or 120,000 cones per square millimeter.

>

> 2) In humans, these photoreceptive cones consist of three types. Each cone is sensitive to red, green, or blue light. This is called trichromatic color vision. Birds have

> an extra cone for tetrachromatic color vision. This extra cone expands the visible light spectrum, allowing birds to see ultraviolet frequencies.

>

> 3) During low-light conditions, both humans and birds rely on photoreceptive ‘cell rods’ in the retina. The human eye has 200,000 cell rods per square millimeter. Some

> birds, such as owls, have up to 1,000,000 cell rods per square millimeter.

>

> 4) Bird eyes, on average, account for 15% of the mass of the bird’s entire head. Human eyes, by contrast, account for less than 2% of the head.

>

> 5) Bird retinas, in contrast to humans, contain no blood vessels. This prevents light scattering and thus provides birds with greater visual acuity than humans.

>

> The decals are very non-conspicuous; after a while, you may not even notice them, but birds will!

>

> Thank you all,

>

> Neil C. Johannsen

> Kitsap Audubon

>

>


Christine Southwick
Pharmacy Administration
University of Washington Medical Center
Box 356015
1959 NE Pacific Street
Seattle, WA 98195-6015
phone: 206-598-7398; fax 206-598-6075



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