Where can we find the correct threat factors for materials?

Just for clarification, did you look at the full credit language under the Pilot Credit?  It provides a description of what needs to be addressed working with the calculator. https://www.usgbc.org/credits/new-construction-core-and-shell-schools-new-construction-retail-new-construction-healthc-212?return=/credits/New%20Construction/v4.1 and the bird collission threat rating calculation spreadsheet can be accessed from the Pilot Credit page or below: https://www.usgbc.org/resources/bird-collision-threat-rating-calculation-spreadsheet Also, have you found the summary of threat factors in the Resources Tab--this can help you with some of the sources, for example, an opaque metal or brick building. For glazing--look up glazing types paying attention to the specifications for each pattern, size and surface of the options.  It is best to have the glazing manufacturer provide the specifications and threat factor:  https://www.usgbc.org/resources/bird-collision-deterrence-summary-threat-factors Other resources are also available on the Resources page.  Hope this helps.  

I found some additional more specialized materials in the American Bird Conservancy Threat Factor Table the published to meet NYC's Local Law 15.  https://abcbirds.org/glass-collisions/nyc-threat-factor   -   https://abcbirds.org/wp-content/uploads/2021/01/Master-spreadsheet-1-25-2021.xlsx If you can't find your material on the credit's table, you can make a narrative explaining why these values apply to your project.