If I was primarily looking for a recorder for wildlife and natural soundscapes, these would indeed be the places to go, but I think I have been given some valuable advice and plenty to to think about, from asking here.
So I appreciate everyone's efforts :-)
I think you misinterpret my post; as I stated, there is a lot to be learned here, but you should definitely consider how different the contexts are.
To put it in numbers, assume that a birdsong is hitting about 86 dBSPL at 65 centimeters. I took these values from the first
paper I found that published both numbers. Note that this figure is the upper bound of the 95% confidence interval for the loudest bird measured; there is considerable variability between the birds (~ 12 dB), so this is actually the best-case scenario (for this species, at least, as there must also be quite some differences between species). Anyway, taking that as a ballpark figure, at 20.8 meters you are at 56 dBSPL and at 166.4 meters that call is at 38 dBSPL (these distances are powers of 2 times the original 65 cm that come closest to your stated range). By contrast, 100 dBSPL, a not atypical taper SPL, is more than 128 times louder than the 20.8 m birdsong and more than 1024 times louder than the 166.4 m song. At the 20.8 m distance, a microphone with a sensitivity of 10 mV/Pa (kind of a typical taper mic value) will generate an output voltage of ~ -76 dBu, while a more sensitive mic, say 20 mV/PA (similar to the Rode) will output ~ -70 dBu. These voltages drop to -94 and -88 dBu at the greater distance.
The long and short of all those numbers, assuming I did the math correctly (a major assumption), is that you’re needs are dramatically different from the typical taper. As I see it, you probably need high-sensitivity, low-noise mics with either a quiet, high-gain pre and a decent recorder or a quiet, high-quality all-in-one recorder.
Missing from all this is the reflector. I don’t know anything about these, but, intuitively, there are several factors to consider there. First, it should provide a substantial boost in gain, but this will be strongly dependent on frequency. So if you are primarily interested in the notes the bird is hitting, and not the dynamics, then it should work well. The dynamics will be off, though. Second, it should lead to strong increases in directivity, again closely correlated with frequency. To capture the highest frequencies, I would guess this requires very careful aiming of the dish. Last, there should be some focal point where the diaphragm of the mic should be placed. I would guess the tolerance is pretty tight with that, too, which probably played a role in 2manyrocks’ results.
Anyway, I don’t know anything about nature recording, so take all of this with the appropriate dosage of salt! Which was really my point...