2 
vocal and active species were: 
Parus sclateri - apparently several families 
Sitta pygnaea - about 2 families, a very vocal nuthatch, 
plso active in the trees, but not noisy, were one or 2 families of 
Clive Warblers, Peucodramus taeniatus , 2 C olaptes caf er , 1 or 2 
Dendrocopus scalaris , ( and occasional Stellar Jays, Cvanccitta 
s t e 1 1 e r i— wh i c W -tiiay ne t have been in active association with the 
f locl^. Two Brown Creepers, Certhia f amiliaris , probably were psrt 
of the flock, but were sufficiently unobtrusive that 1 didn’t always 
locate them when examining the fMclc. A single Dendroica graciae 
was apparently out of the species range (?) and so not a usual part 
of such a flock. 
active on the ground were a couple of families each of: 
Junco phaeonotus - not noisy 
Oriturus superciliosa - 1 think (Blake’s Mexican guide can be 
infuriating in the field, but I can’t imagine what else thhe big 
sparrows could have been); often very noisy. Both species occasionally 
went into the lower branches of smaller trees, up to heights of 10- 
15’ or so. 
We wanted to climb, * I didn’t make extensive studies on 
the group to see who was attractive to whom, but the noisiness of 
the chickadees, nuthatches, and sparrows is suggestive. I mention 
the flock primarily because it is rather more elaborate than the 
chickadee/nuthatch flecks I’m. accustomed to up here. It cane and 
went through our campsite about 3 times in 4 hours . All of the 
species in it should have been resident on the mountain. 
delighted to hear that the sound spectrographs are, indeed, 
useful to you, and that the species is, as it appeared to me, hideously 
complex. You can imagine how I felt while actually running those 
things oi:;, trying to get cut the various nuances by one means or 
another. I hope your friends can get at the low frequency stuflf better 
than x could; they can probably fiddle with their machine. 
1 see that I’m late in replying to your request that I lock ever 
your drawings of them - naturally I’ll be happy to, do send them 
along. And let me know if the 3E people get better resolution, as I 
may be able to learn some techniques from it. The machine 1 used was 
a Kay Electric Cc., hissl lyzer - presumably the same as theyr model. 
1 suspect we might better lock into the problem of ’’echos" in carefi:l 
detail (if not now then in the future), since if one individual can 
introduce this etrect at will into his own voice he may well be using 
it to modifiy his message. Cases where you suspect "fuzziness" of 
being real I might try to resolve with a narrow band filter. As far 
is this business of the pictures being entirely of harmonics of unseen 
i undamentals , this is something I think I’ve probably mentii ned to 
you before, but is without any ethclogical significance flat I can 
see. r resumably the actual vocal chords of the animals vibrate at 
much lower frequencies than the ones we hear (or see), and these fre- 
quencies set up harmonics in the animal’s resonating s ten which 
then selects certain of these for amplification. When t he Sonagraph 
snows a fundamental and harmonics these are really a resonance fun- 
damental and its harmonics. (In tyrannids, incidentally, I sc. etimes 
see a bird shaft its emphasis iron one ‘ahnnonic tc another, occasion- 
ally e-emp aiszing the resonance fundamental without de-enphasiz ng 
one or more of its harmonics - God only knows hciv. ) 
My grant came through about 4 days ago 
tc telephone Kay Electric and place an order, 
is designed to analyse the range S5-8,000cps, 
and my first action was 
Hie machine I’m after 
which is fine for t rannids 
