Greetings all. I concur with Bailey's comments wholeheartedly.
A few comments on the idea that digital photography and measurementsof live birds can adequately replace specimen collection:
1) Digital photography has been a godsend to the 21st century in the field of birding, and to a certain extent, ornithology. However there are a few important issues that it cannot overcome, particularly in field use. One is, lighting. Natural lighting is highly variable, depending on the presence and reflectance of vegatation, snow, and other environmental factors, the cloudiness of the sky, and time of day, not to mention the use of flash. All these factors will affect the color shift and saturation of the photo. Then, there are the settings of the camera, which additionally will affect the photo (graininess, brightness, contrast, etc.). Finally, comparing photos is tricky, as most of us view digital photos on computer screens. If you compare the same photo on multiple screens, you will see that there is a color shift from screen to screen! So to use digital photos to compare colors (say, subtle ones such as different hues of browns, olives, or grays) among different individuals is truly not possible given photos alone. Sure you can use a color chart and have computer screens that are calibrated, but the former would require the bird to be in hand and that the photographer have the color chart handy when they are in the field... the latter is very expensive. Regardless, the results may still not be comparable in reality. Having physical specimens side by side really cannot be replaced by photos, even excellent photos, for these reasons.
2) Everyone takes bird measurements differently. If I measure the culmen from the basal edge of the nares of a bird, and you measure it from the base of the culmen where it meets the skull, the two measurements aren't comparable. Tarsi measurements are even more variable in their style among researchers. Many American banders measure wing chord, but I understand most Europeans measure flat-wing length, so those measurements are not comparable. If a researcher took a set of measurements, then released the bird, they could never be replicated. If s/he took only one kind of measurement of culmen or tarsus or wing, it might not be comparable to other measurements of the same species taken by another researcher. Furthermore, measurements take time, and many folks don't like to over-stress a bird in the hand with excessive handling time, so most likely they'd feel pressured to release the bird before getting many different measurement styles for culmen, tarsus, etc. Finally, what if the researcher didn't think to take measurement X on a bird, but that measurement was found to be an important point of comparison in the future? The potential sample size from which X could be taken would not include the older captured birds that were released without X taken. So, measurements of live birds simply cannot be trusted to be comparable among different researchers, they cannot be replicated (unless by amazing stroke of luck, someone recaptures the same individual), and and thus they cannot compare to what one can do with a specimen.
So, anyone on BF who claims that one can photograph, measure, and release a bird live and thus eliminate the need for specimens for side-by-side comparisons and measurements has a fundamental misunderstanding of the shortcomings of those field techniques and clearly has not handled specimens in the context of comparisons of color or measurements.
