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Hi Suzanne & All, Feb 18, 2008
Good point and this may account for the very different strategy used
by Badgers in Scotland (Nat. Hist, p.51-57, Dec, 1986) and Night-crawler
pickers (head mounted flashlight, stealth and very fast hands). The Wood
Turtle article does not name the species involved and perhaps none of
our orchard earthworms were Night-crawlers.
Getting back to Badgers and according to the above article,
_Lumbricus terrestris_ (the most commonly encountered Night-crawler) is
a staple of their diet. Sett size is determined by availability of _L.
terrestris_ and sett range (50 to 3,700 acres) is determined by the
distribution of grazed cow pastures.
These earthworms are more abundant in cow pastures than elsewhere
(cow biomass ~ earthworm biomass) and Badgers, who mostly feed at night,
can more readily move silently in grazed pastures than elsewhere and
thus catch them before they zip back into their holes.
Yt, DW
-------- Original Message --------
Subject: Re: [NatureNS] Wood turtles and earthworms
Date: Sun, 17 Feb 2008 17:12:30 -0400
From: "Suzanne Townsend" <suzanne.townsend@gmail.com>
To: dwebster@glinx.com
References: <47B8976D.3030202@glinx.com>
When I was a kid my brother showed me how to get nightcrawlers by mixing
dry mustard and pouring it down holes. I just checked this out today and
this site notes that nightcrawlers "rapidly move into deeper soil" when
they feel vibrations.
http://www.nrri.umn.edu/worms/research/methods_worms.html
So if you want to get the big worms, best not grunt. :)
On 2/17/08, David & Alison Webster <dwebster@glinx.com
<mailto:dwebster@glinx.com> > wrote:
Dear All, Feb 17, 2008
I vaguely recall having mentioned this previously in some context,
but in the early 1970's while preparing sidewalls of soil pits for
mapping of apple roots we noticed that scraping the sidewall with the
edge of a small mason's trowel to smooth the surface stimulated
earthworms to emerge from the sidewall. This applied especially to rigid
(shatters under pressure but slakes in water) or compact soil.
I now notice that making use of this response is called grunting
(Nat. Hist. 8-13, Aug, 1989). In northern Florida, earthworms are
collected for bait by driving a wooden stake into the ground and rasping
against it with a notched stick or old car coil spring. The vibrations
induce the earthworms to emerge from the soil surface.
This is all old news but even older news to Wood Turtles in central
Pennsylvania & New Jersey who stomp their fore feet to induce earthworm
emergence (& stomping by Wood Turtles has been observed in Michigan and
Wisconsin). Gulls and Plovers in Europe catch earthworms in damp meadows
by tramping rapidly with both feet alternately or by vibrating one foot
against the ground.
One Robin or one Ruffed Grouse can make an astonishing of noise in
dry leaves which leads me to wonder if this and the gait of robins are
also forms of grunting for earthworms.
And do out Wood turtles stomp ?
Yours truly, Dave Webster, Kentville
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