Subject: [Tweeters] Re: What did the birds do in cold weather before any
Date: Dec 16 20:20:05 2010
From: Dennis Paulson - dennispaulson at comcast.net


Hello again.

As this is a subject of much concern, I'm coming into the discussion again.

Much as I would hate to question the judgment of the eminent biologists from USFS, USFWS, and WDFW, I still suspect those finches, when they eat salt from the road, are going after minerals rather than grit to aid digestion. All of the birds - Evening Grosbeaks, Red Crossbills, and Pine Siskins - that were all over the road on hwy 2 a few winters ago are well known to crave minerals. They collect at fire pits to eat ashes, and they visit mineral springs (as at Longmire). I know of no other local bird species that do this. They are known to ingest grit also, but I still don't think grit is why there were so many of them on the road near Stevens Pass at that time.

I have seen the same phenomena with Evening Grosbeaks and Red Crossbills in summer when there was no snow preventing them from access to grit. I witnessed tremendous mortality of Evening Grosbeaks by automobiles in the Wenatchee Mountains one summer quite a few years ago. Flocks of them landed on the roadside and on the road (I suppose salt from the winter before may even remain on roads), and they were in fire pits in the campgrounds. I don't think there is any gravel in the ash in fire pits. Also, those birds were eating nothing but spruce budworms (we dissected quite a few of them at the Burke Museum), so they had no need of grit. Insectivores don't seem to need grit.

I have been on the road a lot in Washington and have long noticed which birds flush from the road shoulder. Normally, finches are not among them. So either they get their grit elsewhere, or they don't need much. Furthermore, finches and sparrows that crack and discard the seed coat surely don't need grit as much as the birds that swallow the seeds whole. Also, finches seem to spend more time drinking than other small passerines, and perhaps this relates to their mineral-eating habits.

This is from the Birds of North America account of the Pine Siskin:

Pine Siskin shares cardueline proclivity for salt consumption (Bennetts and Hutto 1985), suggesting some mineral requirement not satisfied by its food. May ingest ashes, blue clay, road salt, powdered andesite rock, newly set Portland cement, etc. (McCabe and McCabe 1928, Bennetts and Hutto 1985, Messineo 1985).

This is from the BNA account for Evening Grosbeak:

Also consumes snow, charcoal from campfires (Orr 1951), coal and coke ashes (Parks 1947). Strongly attracted to salt and other minerals; eats salt on roadsides and mineral-rich soil (Downs 1956, Shaub 1956). Attracted to areas where NaCl or CaCO3 experimentally added to soil (Bennetts and Hutto 1985). Salt sometimes used as a bait to trap Evening Grosbeaks for banding (Clabaugh 1930).

And for Red Crossbill:

Takes grit regularly from road cuts, stream banks, and bases of uprooted trees (Benkman 1992a), even mortar (Bartlett 1976). Consumes salt regularly (Aldrich 1939, Marshall 1940, Bennetts and Hutto 1985), especially in winter on roads, though salt is apparently not necessary to maintain health in captivity (Dawson et al. 1965). Observed eating small bones (Payne 1972).

I don't know if those biologists read these accounts or not. The BNA account of Red Crossbill mentions them eating grit, but there is no mention of this for Pine Siskin or Evening Grosbeak. Wouldn't tiny salt crystals melt in the GI tract of a bird and thus be of no use as "grit?"

Dennis

On Dec 16, 2010, at 6:37 PM, notcalm at comcast.net wrote:

> Hello group.
>
> These posts now have my attention. Do others have thoughts and reports on similar mass deaths?
> I certainly enjoy viewing birds. Perhaps some of us can think about what we can do if this turns out to be a significant problem.
> We have a lot of creative problem solvers in the group. If there are patterns to the locations and history of events I would like to know more about them.
>
> Janet, I have attached your post so that others can follow the conversation.
>
> Thanks,
> Dan Reiff
>
> ----- Original Message -----
> From: "Janet Millard" <tilia at drizzle.com>
> To: tweeters at u.washington.edu
> Sent: Thursday, December 16, 2010 12:18:20 PM
> Subject: [Tweeters] Re: Birds sitting on the road in rural Eastern Washington
>
> The event described below was all to common to us residents of Leavenworth
> and surrounding areas a few years back. Hundreds of siskins, finches, and
> possibly crossbills were clobbered all winter long, mostly along the
> section of Stevens Pass from Mill Valley nordic center to Yodelin. We
> sent our reports to WSDOT who did some analysis - and biologists from
> USFS, USFWS, & WDFW all chimed in. The conclusion we came to was that
> these seed-eating birds needed grit to process the seeds in their crop,
> and the snow that year was amazingly deep. Without a "natural" source of
> grit they turned to the roads. The problem was the salty material that
> was sprayed on the roads to reduce the icing for safe travel. The salt
> was injested along with the grit, causing a sort of "salt poisoning". The
> birds OD'd on salt and were mentally/physiologically incapacitated to the
> point that they were not able to avoid being killed by cars. Entire
> flocks were sometimes killed with new flocks seen foraging for grit among
> the dead. Tragic and heartbreaking.
>
> Janet Millard
> Leavenworth, WA
> (USFS wildlife bio tech)
> ----- Original Message -----
> From: "Dennis Paulson" <dennispaulson at comcast.net>
> To: tweeters at u.washington.edu
> Sent: Thursday, December 16, 2010 1:37:15 PM
> Subject: Re: [Tweeters] Re: What did the birds do in cold weather before any paved roads
>
> Dan and tweeters,
>
> Having worked in museums for all of my adult years, I can tell you that grit-eating birds are among the most common road kills received by museums as salvaged birds. Doves, pigeons, gallinaceous birds, and Horned Larks all feed on or at the edge of roads, as none of them crack seeds with their bills in the way that finches do, so they need the gravel to aid doing so in their stomach. I think corvids probably are similar, and when you see jays out at the edge of the road in forested areas early in the morning, I suspect they are getting grit, true or otherwise.
>
> Thus I don't think putting out a few grit feeders will alleviate the problem, as it's happening all along our roadways. I don't know if there are any recommendations we could be giving to state Departments of Transportation, but someone might look into that.
>
> The feeding of crossbills, siskins, grosbeaks and other winter finches along the highways, sometimes a great source of mortality, is probably not for grit but for some mineral(s) on the road, possibly even the salt put out by road departments. Fortunately that's a rare event.
>
> Swallows sometimes land on roads in great numbers, and that's another thing altogether. That may even have to do with retained heat on the road surface.
>
> Traffic on roads certainly represents significant mortality to birds and other animals, but other than very local fixes (tunnels for large mammals, special herp crossings in some very few areas), I don't think much has been done to alleviate it, and it's hard to imagine how such mortality can be reduced for birds. Very wide clearings along roads in forested areas probably keep small birds off the roads but also represent barriers to dispersal. Fewer and slower vehicles, anyone?
>
> Dennis
>
> On Dec 16, 2010, at 12:04 PM, tweeters-request at mailman2.u.washington.edu wrote:
>
> Date: Wed, 15 Dec 2010 20:24:41 +0000 (UTC)
> From: notcalm at comcast.net
> Subject: Re: [Tweeters] Re: What did the birds do in cold weather
> before any paved roads
> To: Scott R a y <mryakima at gmail.com>
> Cc: Tweeters <tweeters at u.washington.edu>
>
> Thanks, Scott.
>
> It seems the problem is not limited to these two species.
> If the primary reason to approach and land on or next to the road is a search for grit and more so than or not heat, perhaps we can arrange for certain small, off road, non- parking areas to be cleared for that purpose. Grit would certainly be easy to add. It might be an interesting experiment in mountain passes, if grit is not readily available in snow covered areas. It would be the equivalent of a small, protected area with ground level bird feeder (true grit only). The gulls on the other hand(great photo) are probably not looking for grit.
>
>
> However, I do not know if it is a significant problem. Does anyone have estimates of mortality for these situations? Perhaps it is rare.
> Have any of you supplied grit in a small area in your yard?
>
>
> Dan Reiff
>
> -----
> Dennis Paulson
> 1724 NE 98 St.
> Seattle, WA 98115
> 206-528-1382
> dennispaulson at comcast.net
>
>
>
>
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-----
Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382
dennispaulson at comcast.net



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