994- UC-NRLF data is not for publication without consent of the Forest Service. ) SS D-6 Columbia - Studies Nursery Experiments. RODENTS AND FIELD SOWING By C. P. Willis November 19, 1912. ---o--- The study was started on the T/ena tehee National Forest after observing serious injuries to seed spots by rodents boring into them and eating the seed sown. A se- ries of tests was carried on on this Forest with the ain of obtaining some substance so repulsive to white-footed mice that seed treated v/ith it would not be molested when sown in the field. Mice were kept in captivity for the tests, and were fed untreated and treated seed each day. The following is the summary of these tests: Wenatchee Tests with Gaged Ilice (See file copy of prog- ress report. ) The following table shows the substances test- ed with white-footed mice, and the value of each accord- ing to percentage of good seed left untouched. •*- ;tr, .\fahs Library •7- 'I- _. « - . « r - . -.-.< : j r.' j, r i . j ;.i r fv* •-*•-•' Number of seed left for Substance used in Per cent different mice treatment of seed Mouse House Mouse House left 7 8 9 10 Zenoleum and sulphur 60 30 56 9o# Zinc chloride 56 0 72 no lodoform 54 76$ 50$ 36$ Nux vomica 44 60 74- 5# Nap thai en e 43 7# 42 78$ Tincture of iron 19 20 Glycerated asafoetida 14 0 30 Tannic acid 16 0 35 Carbolic acid 6 6 Powdered sulphur 2 2 Zenoleum 2 2 Tobacco solution 1 1 Copper sulphate 1 1 Lime and sulphur 0 0 Borax 0 0 " Glycerine soap 0 0 Mercuric chloride 0 0 Belladonna 0 0 Tincture red pepper 0 o# Quinine 0 #150 treated and 1JO untreated seed were each day fed. All were Douglas fir seed, "but two different lots 7/ere used. In one lot a count of 500 seed showed 105 out of 150 had kernels. This lot was used where the # is not given. The othe^ lot had 97 good seed out of 150 and this was used where a # is given after the figure. It is thought that the test was severe and that where 40^ or 50^ of the treated seed were eaten in the cage that few or none would have been touched in the field. This is merely a supposition based upon the following facts : The mouse was in each case confined to a small space; he was underfed; the treated seed was easier to reach than the untreated seed in the cage. -2- ;.• • ^?'V U> ----- •^ ^ Zt~* ' t"; ' I > '* Ox \ on \iv ' ••oc '"<•>'" ?- • . — , • _^ o M < " ' "f^'^ ..•': - ''••*- 0?'I io-'- . • /:»' '• ' ' • ' '^o ;;::;'> ;-or-; ax -' " ' •:••:•-.:/• - '-^:fj «f i nlT-frT^x '^O ^UO 1 •,...• £ ' W ..-.1 • •' '-rtL^ *iv --»_-. ::. -v. :,_ . ;V*^T» ri^v: ^i.:4 i*:.: ^?; .. :'t -:;- ^* 'iS " " • ' " - -'. ../. .vf» or * T l--r . . .^. ..to^? Jbr-r -> ?v :» £*»*:„* ^:.,: ';, C" ;o ^0^* ^T^?;: lied'BSir : . - .- -..•.. . '" ^nit/r •:) i;i a *9* ^^ a b^-js^Tj' 9 .?--.. tfW ;t. • £"• ' - (ti — C» '•. Wind River Tests with Gaged Mice and Chipmunks: Tests similar to the Wenatohee ones were a few months later carried on at the V7ind River Nursery. Zinc chloride, which was next to the best sub- stance -cried on the Wenatchee Forest, failed absolutely. Two tests were made with different mice, and in each case all the treated seed were eaten. lodofonn, the third best substance on the Wenat- chee, was not used in the sanig form as previously, but in the way it was us ed it failed. Instead of putting the iodoform on the seeds, it was placed on the surface of the earth :ir which seed was buried. One-fourth teaspoonful was cpvi.uTOLed over soil in a box 5" x 6" in size, but seed buried '1-1/4" under it were smell ed and dug up. Hap thai ene, fifth best on the Wenatchee, wae «. used ae in the case of iodofonr placed or: the surface of soil in which seed was buried, instead of on the seed as formerly. In the form used last it failed. ITux vomica, iodoform, starch, and flour, made into a pellet 3/8 tf to 1/2" in diameter, inclosing 10 seed, was only fairly efficient. Of b pellets, two fed to each of three mice, 3 were nibbled, .1 broken to pieces, and the seed eaten, and 2 were left untouched. The only conclusion which can be rnaae is that -3- • .-•; ;..:._•• .• .--.riv. :>.rv:. :;;:, .. . - .'•; *£#£ '-'-'•' i ' v -"-': -•*' c-;~~ ' » • ..... " ~--' •"''--• r.-v j..: ;.. , : : .--'i-: d : -;"::- ' • • - - - ' '-•••'• f9^'9t%i^f- •" " • - -: '•" •• . . . -.-; '":.:'.: ".-.'' - : ' " ' . 5. -• i j$£l « ^;-'- fe9' r: ;-- S •"•:"•'-'-" • i '-' • • '•'" \- '•'-•' >M4 '• &•* • ••: •• • : ' • ' ••• : ' •...;.- ". .".•• ..-. . ... •• . ;. . : c .-.:»'. "- f , . -.' - ' :. . .L . - '>• - ,. % . . . ,. the Wenatchee tests were not as severe as was thought, and. that the ideal substance is yet to be discovered. Various other pellets, pastes, etc., were tried and among them only one form of one mixture gave satisfac- tory results so far as protection goes. This was a pellet composed of equal parts of tannic acid powder, tincture red peper, tincture of "belladonna, and enough flour to make thick paste, the whole enclosing ten seeds and being about 1/2" in diameter and four sided. The pellets were used twice with one mouse, once with two other mice, and once with two different chipmunks, and in all cases formed perfect protect ion. The seed, co-old ha idly be sown in rush foim, lio*rf-,T e:r, as it undoubtedly would take too long tc germinate, BO -chis substance i^ -.iCt practical. The sf.nxe mixture in paste foim was of 5°> 'approximately) value, failing absolutely in one of two oa/.ee. The omj ;• G ion of one of the poisons seemed to nullify the protect! ve value. Alter tests in the treating of seed with repul- sive substances had been carried to this point, it seemed best to try other methods of prot-ccti on. Accordingly seed was enclosed in screen wire cylinders, about Iu nigh and 1/3" in diameter, with two thicknesses of wire as protec- tion to the seed, since it was eoon fcunrL that 'die mice could nibble the seed wten but a single thictaiess was IB ed. -4- •' • • agic fl .:s. u*.j3 , . '-- .: .;;"[/. ( I f r anol oo.d J3UJ bioo-K • .' . ; 95 - •• . • .. '.- Cage tests indicated t-iat this was sufficient protectiov to the seed. To give further tests, a nursery bed frame was made mouse proof, spots representing seed spots we:;.;.. sown over the ground surface enclosed, a couple of mice were turned into the area, and the results following were obtained: Results of P & S No. ?: There were seed spots in the experimental bed. These differed from one another in the seed being encased in cartridges of screen wire, or not so encased; in different sizes and forms of the cartridges; in dif- erent depths of covering; and in different number of seed per spot, as well as firming the covering soil or leaving it loose. Encasing seed in screen cartridges is not effi- cient protection, llany of the cylinders were dug up, others were exposed by the mouse digging around them, while seed was extracted in two instances by the mouse gnawing the top of the cylinder and reaching the seed in this way without digging up the cartridge. It does not seem that the cartridges could be used even if they gave better protection, for the stems and roots of the .cod-- lings do not extend vertically, and consequently ait more apt to pierce the sides of the grlinder passing through -5- • I' ':•;: :. •';:: :P.$T •_• . . : ft fo'j ,;cf I.w" B&r NB3; .. -..,. .. .--- . "T ^V . / " r : V .Q.*£ ': :: ' "'•• • "•:••', '.^ •• -.- • . ^~n. .. I '•-••- :•«•;•• -*.: :* . r ' ... ... ' W%^ : 5 ^/W®; •.&• '" v -.r : '-^o '• .• ,.v. - ..... . , .' :. ;^ ^^j-mi'l a^i .- . t rocrs "- •:. ' ' -' ..-•',. -.>n • si w^e^V **>; ;jo ru. ••' . ..; :.-::-r . --i v- :;i .: . .^--- :;. -:io"-; sT.ob.-jil-;^ . ! - ^-.- . • ..-••-.:-.:- i:ru;i-r.. : ;• ' •?::'-"-i fi--.' - . •••"•••>v: :.-•-. :~n • -• " ' «*>-- - •'• .*n - ' ' '• ;- •''-' • bKf- • ':c> ;;0~ ^;{^ \\r\l\- &u:-\ .. . .. ;-:--,:i: v,;c;.r-— --w ^--1.: '- -• " - -..?- ":o"l. .. :;r^ TO': the wire mesh, than to miss the wire by passing through the openings of the cartridge. The ordinary method of oeed spotting, 50 seeds to the spot, 1/2" covering of soil, either firmed or loose, gave as good results as any other method tried, but never- theless suffered greatly through the mouse damage, tfotes dm the Smelling Powers of ITice: In the last experiment seed was sown at depths of 1-1/2" and 2-1/2" in some of the tests. Part of the seed in the 1-1/2" sowing was dug up, while the surface soil on one of the 2-1/2" spots was nosed. It is obvious, therefore, that mice can smell seed even through 2-1/2" of soil. Since deeper sowing than 1-1/2" would make the coming up of the plants very uncertain, it is not possible to sow seed deep enough to prevent their detection by rodents. In cage tests a box 5" x 6" x 1-1/2" was filled with soil, seed sown at a depth of 1-1/4" in it, and iodoform or napthalene spread over the surface. The following instances show that mice detected the seed despite the strong smell of the substance sprinkled over the surface. (Only the first time the box was put in a given mouse's cage is considered, since on repeating such a test there is a chance memory rather than sense of smell rcould cause the mouse to dig.) -6- . :-?r~,., <,.-> ' ... . . . . :- .,.•.:•••: ": .v Lor"/--' vv. ;•-..: '•'•"• -. . . ' :. :•:'.: : |HMN || 9 :. .::"•. V :x> " ' . -.-:;. , • • .- • : • -;..^- ..- • - -• ^^17>/ j^Pi^ ^^ a?e---.?'- ..; ; :;• .- •• . nd nu.:-:.- •• *.;: RWff^ M19 ; --•- .•,--.-;- ^ *6^I ft- • <«-';? • • ^ %£«^qe^ o/Tt ta ftir^s;? - iiO I.tC;.; :.-S-'-:yfk'a ^^ ^IlltV , tf 8^1 - ..: ; • ..- .. • '- ' :'--; .,'-.;t0*4'i£ (S^\mft .- ; :;.'-:.::; tSQ OPJ .. : '.':'-. ' " . . ' " blopw »S\ .>•»*. :. -,:;•.•;.: ,-; .. •-;•; • .;& wot || ... [i8$Qq n a^ ^i .. • •— : • :• .- •• • . . %a?S19V. -: - ; ;-•;• .-- . - , .- r \ - ' '. , - / . .. :•• -' :•; . ' :-• "- • • *,* i -_^ •; ^ »A ., - t v %ap*litv r?-» b*.- •: -.. ; , ^L...-,^ .'- '- '"•- ' - ' ' .••;•. &$&$ ^44X1^ TV k1 ' ''' ' - -•'' - ."-, . ••-. .._:.•. J-V'i -• ^ '• ' - ^ ^-••- • - :• ••• -:- :: ', .-:. ••--• -:>. . -•: • "r i -- '-'- ' • - - .... . ' *3 . :,;•:: \,^ij> Py ..• .:j£o t.. JUss^ "r.: • :...-. • -i i* ^^-- With Mouse 11 two moth balls (napthalene) we;?e crusliej. and put on the soil surface. The first night the mouse dug into the box. "but only went to a depth of 1/2", ani there- fore did not reach the seed, though it seems he must have smelled them; With Mouse 12 a similar test was carried on, but in this case one-fourth teaspoonf ul of iodoform was put in the surface. In one night 4J;J of the seed in the box were dug up. Again, with Fouse 13 a test similar to that with House 11, except that the napthalene was placed in a layer over the seed instead of on the ground sir face, was carried on. Approximately 5°^ of ^e s66^ were eaten in one night. In the field seed spotting on Pilot Knob (P & S 2) most of the spots were mulched and a few were left unmulched. Signs of mouse damage were verjr evident in the unmulched spots, and apparently almost absent in the mulched ones. Two spots mjLLched in the mouse-proof nursery bed already mention- ed apparently were not dug into. Ho seedlings came up in these spots, however , and it therefore is not known whether the mulching actually prevented the detection of the sown seed by mice, or whether the debris accompanying the mulch merely hid the evidence of damage. There appeared to be a strong probability, however, that the smell of vegetation -- in mulching — might be strong enough and of the right nature -7- ..... S . • . . • • •"--• : • •.-_ ..- • . 'i •:•::.:•-. .--.. •>-•- . - :.:..-. as -•• - • • -•• -; • '•• _, L.a: |&tiiij ••• m fli • e: 4 " ' •••>••' -i- . -: '*: r • •;.-••. - •" . ;; • -" ... - " . -. . . ' •'''' 'n :?* *•' - ' ..;•:'" • •? - -;-- «•••'• •- • •• £ ni .baojslq a^w &a»l£r(crqfiii S;L> cr^ii^ *< tH ..- .- i - • = • - • .-,.';'• . : T0 ------ ... «• ,.--.- .-• : ->.-?:• ?r .':'1 -^' ': ^Oft^^ai' : - >qs bsec.' .- :- ._ ;. r,.-^. . .:/;-;: jlal -f>io- Efi -•-- : ' -«?:oqs.- ,-: •. . -.-. ,. • l-nsiii • - -.,-••• -. • -;.v_.; ; • ... . ,. . ; . - , ..,;,••; •:• ' : ' '••-•.•:,.:.•. ., - . ...... . »ot - Pt 9 ; ._ - ; - : *• . \ •-'. , *.» ^^»»- .... r,,^ .f.^0.; ax Qio'rs^ . . • .- . •- ;- • .;.-••' -. . ! • - - • 3 gfi.: .. - _;;: -.» -. • - .;.... •. : .. « ':. jjons 3 sd" cfifsiffl -- gnirfolina ni to deaden the smell of the seeds, and so prevent their de- tection. To test this point the following sxper.i.nniit *-iras made: Re&lilts of P & S No. 8: A nursery "bed similar to that of P & S 7 was made mouse proof and sown to 46 seed spots, each with 3° seeds covered 1/2". Ten spots were left unmulched, and various sorts and amounts ot mulch were used on the other spots. The nun* ber of seeds which germinated per spot indicated the effi- ciency of the mulch in protecting during the period the spots were exposed to the attack of a mouse turned into the bed. The mulch did not prove effective protection, "but it apparently had a slightly "beneficial effect , at least when its depth was over 3/4". The following is a comparison of mulched spots with layers of mulch 3 A" to 1-1/2" deep, ant,'. unmulched spots. There were ten of each. Class Seedlings per spot Spots with seedlings I'ulched VAn. 0, Kax, 5, Av. 1.4 $0$ Unmulched Mi.n. 0. I Sax, 1, Av« .4 40^ All of tilt; umiuiched epcts and 6p^ of the above mulched s^cts load been dug into by the mouse* No evidence of digging was found in four of the well-mulched spots, biro is ib not certain that they were unmolested. The spot -8- • *» jy '- '", • '-.*.»' :'-• : ,,. . -u 3-joi'i;.:" &n--. .. • • •ri^n ••-. • •* - - x Ti * ;* f;:v ': • J - • ' | , . . . ' ' ..'10m ' ' '' .olio'. \ ,- .... ...... ... . .- . . • ' I •: ' .a: ^r{olA/frr-j:i& . - • •' rttit -'-•; ?• having the highest number of seedlings (5) had certainly "been dug into, Extent of Damage in Field Sowing: Area Ho. 1 of the field sowing was devoted tc- de- termining how seriously mice and chipmunks damage seed ---pots* One-fourth of the spots were caged with wire screens, pre- venting rodent digging, and the others left uncaged. Hilf of the area had the seed covered 1/2", and the remainder had I-1/211 of earth over the sown seed. Gemination was very poor and for this reason no conclusive results were obtained. On the area, comprising 1/6 acre, 15 white-footed mice and 6 chipmunks were trapped. Prom the looks of the seed spots it was judged that 9^/j of the damage done was caused by white-footed mice and 2/£ by chipmunks. In the 1/2 M sowing, <)6$ of the spots had "been dug into at the end of 11 days, while 76$" of the 1-1/2" sowing Imd been similarlTf damaged in the same time. These figures ap- ply, of course, to the uncaged spots; there was no damage in the caged ones, since the screens pror ed very efficient protection. The germination results are not very sug^ stive, owing to the general poorness of germination. Even in the protected spots and the shallow sowing it was very poor. The number of seedlings per caged and per uncaged spot dif- fered little. Of the caged spots, 60^ had no germination ' «**- ? '*"' "v- -- - '' ;:- "" ;-. ;:_••'/ ..-•;..:.. .- '.-.3 " . •-• ;-..,: ..-..:• • . ci\ • j • . - ' =/. v .• '•.$ : . . / .: ' .^ • -':.•: ' : --:,-:' ::. i-.--r: •.. ;- . / '. f . : -- - .>£ '--.' -;r;vo f^*. " / "j£ ~:o ; v -; v- :^i:;-,.v;. ,:;-:•: :»I ' • " • && &Z9V7 8-d-HT ' - ': ' - ' •' :'; « ' - :• 3 w-ooY^ ^ ' • r- •• • .;•'• ' •• -;;" -^ ' 1 ' :• ' ;•'. Itf-^j ---^ g >o •' '•" - - ... rt)^li - ' •1.^- bse' •"''"• : - '• • '-' '• : -OB -^SVJT ; ' • ' : . . •• -. ;..-. _. ::• ;. o| •-• <.... ':.: : ' ., : ',' • .. • : •:-••;• :?r g ; :: ...- i ri '. ' . -. ' - • •• :.,-•.. .// - ..,;. ••.-_• . - ::, .••. " : . ' : -7:.' -. • • • •;; . D- .:., ^jrjj .. | ^] • - -. • --:::.^ ' " ' ,HG*'.'V. ' ' - .' ' . . •••-. '" " '•"".' ' ' : : :--• • : '; --.',.-. • bJ -:-' :•:-'• ".-•" -^:^ -• . -' •:••: .. .. while 71/j of the uncaged spots were without seedlings. The most seedlings per spot were in an unprotected spot. Ger- ij4 1 nation was almost an utter failure where 1-1/2" of soil cov- ered the ceed. On P & S No. 3j at least 82$, and probably more, of the seed spots had been dug into by mice or similar ani- malSj when examination was made July 22, 1912, a month and a half after sowing. On P & S No. 4, a count on the north slope showed 86$ dug into and one on the south slope showed fji?$ of the certainly dug into by rodents. The time of sowing and of examination were similar to P & S No. 3* On P & S Ho. 5 1 w&ere the spots were made with a tamp, and were 3" in diameter arrl lt! to 2" deep, a count on the north slope showed at least 73$ duS into by rodents, and one on the south slope showed 76$ molested. Results of Poisoning 20-30 Acres in Spring, and Sowing Seed in Fall: P. & S. Ho. 6 is an experiment in poisoning to rid a small tract of rodents so that seed could safely be sown on it. The trial failed. The area was poisoned with strych- nine-treated wheat on June 15, 1912. The wheat was poisoned by Dr.. Dea.rbcrn of the Biological Survey, and was distribut- ed partly "by him and partly under his direct supervision. To -10- •V*£- :' ' :::'' ' • '•"' .:-. "; . •• - ;-:-: frj •""' ';; '•' ' i ':-:":"' * -i -f JT- ••- ' ' , , ..--. ... 5- ' " ' '" * • • ' ...... ^ . .,:;... -• ' ".| Hb e - • ... .•• .::: ; ^:T// ; jolc •'- - ;-- -^;:- • ; - ; - ' ' l *"' '" a "bushel of wheat, 2 ounces of strychnine in the alkaloid form and 3 pints of tallow were used. (On the lit. Hebo poisoning, Kraebel gives the folio?/ ing figures: To 5 gal- j'j-s cf wheat, 20 teaspoonfuls of strychnine and. one quart of -callow The strychnine and tallow were mixed "before ap- plying to the wheat, but this was not done in the poisoning of P & S Ho. 6.) (The poisoning on the Mt. Kebo area w«,8 more severe, since 1 teaspoonful instead of 1/2 teaspoonful of strychnine was used per quart of wheat.) Since the wheat was :V>.stributed at the rate of 1 bushel to 20-30 a- cres, 1 quart to 1-1/2 quarts was used per acre. (In the lit. He'oj poisoning 5 according to Kraebel, the wheat was distri- buted L\t -he rate of 2 to 3 quarts per acre.) Oi.' July 27 most of the wheat seemed to have been eaten or carried away. One dead mouse was found; some ker- nels half eaten showed rodent work; seme bird feathers were found near piles of ™>ieat. On October 26, 28 and 3°i part of the area was sown to Douglas fir and western white pine. The sowing of the 26 tli was examined on the 28th, and one count showed 80;£ to 96^3 of the spots dug into. Another count made nearer the center of the tract showed 80)£ to 90^ of the spots mo- lested. This was after two nights. During the same time four mice were caught in five traps and the bait of the fifth tiap had been nibbled without springing the trap. On -11- *.T! 1$ . . : ...... .,,... . • ••-„••• •• ?•;• • • 1 : . • ->... • • '•' ..... •' . ., „ . . * ,. .-. ,j-. • • • — .... ' , ......_,- "• - - • •• .-/•«. . , - • . __ • ' 3 ! :• . , .v . . ; . • -_ j. ' t . . ,, ... .V . ..-.,.,. . . .. .. . -f . . . - "ic ' . . i.;.c -..-,-.. * . * • .'..,-•.*-»?• - . t*- * . • - v--' , \ • .-•-•• :' ' ' ' ' - October 30 the sowing of the 2oth was examined. On a strip through the center of the tiact lOOJi of spots where seed was covered 1/2" deep appeared to have been disturbed, while 91/£ of these undoubtedly had been burrowed into, since seed husks were found on them. In spots similarly placed but with seed covered lft deep, J2/0 appeared to have been molested and 38/4 &ad surely been dug into, as shown by the husks of eaten seeds on the spots. As with the pre- vious count, this damage was done during two nights after sowing. As before, in this time four mice were caught in five traps, and the bait of the fifth trap had been nibbled. The traps this time were set as near as possible to the cen- ter of the sowing area, and about in the center of the area poisoned. It is evident, therefore, that poisoning a small area in the early summer cannot be depended upon to rid the tract of rodents to such an extent that- seed can safely be sown on the place in the following fall. -12- - '. ' ^ -f "*» '- . o ; • ;' ..- . .-. '