Hi Greg
Hopefully, you can make sense of the below,,,,
Referring to your question about ISO here:
http://bioacoustics.cse.unsw.edu.au/birding-aus/2010-07/msg00379.html
I am definitely no authority on photography but can recommend always choosing the fastest shutter speed possible for flying birds to freeze motion (which is probably what most people would want me thinks). Getting the fastest speeds means using high ISO 400 to 800 or even more, and depending on the camera body and your exposure technique (which I explain in more detail below) the noise will be still quite acceptable and most certainly manageable with plug-in software such as noise ninja or Neat Image (I use Neat Image and love it). Though, the more you pay for the camera, generally, means you will get better noise handling capability due to the quality of the sensor in the body and generally better quality images straight out of the box. But, one’s ability to be able to expose correctly (in a digital sense) will also determine the noise evident in the image and it’s quite possible to get great results from entry level gear too. Generally, I never shoot below ISO400 even in good light, I don’t have a noise problem because of how I create the exposures in the camera. It takes a little practice and getting used to trust the camera’s histogram! 
First, one needs to turn on the histogram preview option via the camera menu. It shows the digital exposure for each image taken. MOst cameras should easily handle ISO400, even the new, entry level DSLR cameras. Sometimes, and not often, will I shoot at an ISO up to 1600, but then the exposure becomes even more critical than at ISO400.
I have learned and applied with reasonably acceptable results the following: to minimize the graininess or noise, one should try and overexpose the images to a point WITHOUT blowing the white tones in the image (by clipping the histogram on the right side). To check this process, one needs to understand digital exposure in a bit more depth than looking at an image on the back of a camera and judging by one’s eye whether the exposure is good or not. The histogram is the best friend to any budding digital photographer and is a graph showing you the exposure that one made by the graph, which really represents tonalities from the left of the graph to the right as black to white. In other words, the left of the histogram is the blackest of black pixels and the right of the histogram the whitest of white pixels with the peaks in the graph representing the number of pixels for that tonality. The middle of the graph is around the old 18% grey mark (if you know what that means). The histogram is numerically representative from 0 to 255 with 0 being black and 255 pure white. Now, the trick is to expose the frames with as many of the pixels getting close to the right side of the graph without any clipping of the white tones (clipping means you lose detail). This means that when one looks on the LCD on the back of the camera, the image will look like total, utter crap, but the correction to a more visually pleasing (and correct) exposure can be made when one converts the image from RAW by reducing the exposure in the RAW conversion software; whether one uses DPP, Aperture, ACR, NX or Lightroom. Needless to say, it is always best to work with RAW files in the camera to maximize the detail captured and the post processing will be far more superior than those shot as jpegs that will not have the range of tolerance when it comes to correcting (in the post process) a poorly exposed image. Which does happen too! Even to the best out there. LOL!
Feel free to ask more questions if something is not clear. For example, I show you this image I made with the following gear, HAND HELD. If you do the maths, the field of view equivalent is 1,344mm with the sensor being APS-C thus having a 1.6x crop factor. (300mm + 1.4x + 2x = 840mm; 840 x 1.6 = 1,344mm) So having image stabilization in the lens also gave me some more security to get an acceptable image. It is almost full frame from the sensor as presented.
http://www.amatteroflight.com/wordpress/wp-content/uploads/2010/06/Focal-840mm-Brown-Falcon_0041.jpg
Canon EOS 30D, 300mm f/4L IS USM, 2x + 1.4x, ISO1600, f/16, 1/250th, +1EC
Of course, my camera is an old, obsolete, 8.2 megapixel heap of junk in today’s world of technology; being four and a half years old. Yet it’s more than capable of producing images that are and have been published in calendars, cards and books as well as prints to A2.
I have written two tutorials so far that you or your friend may find of some use. You can download and read the pdfs here:
http://www.amatteroflight.com/tutorials_files/CHECK%20FOR%20CLIPPING.pdf
kind regards and best of luck
