N5xtr, are you referring to "all federal land" ? Or just federal land that is a "wild-life" refuge ? Do not make the oft-repeated mistake of thinking that "all federal land is a no-no for md'ing. This is not true. There are various forms of federal land with no prohibitions (silent on the subject). And others with outright express allowances (BLM, NFS, etc....). So it's simply not true that "all federal land is a no-no".
And I'm not sure if the OP's particular wild-life refuge is even federal (perhaps it was state? county? etc...). But for sake of argument, let's assume it is the type of federal land that's the sub-set of wildlife refuge. Where are you getting that md'ing is not allowed ? I just looked it up, and find no specific prohibition. Here's their listing of rules:
eCFR ? Code of Federal Regulations
And the most I could find, that *possibly* could be construed, is the following:
§27.62 Search for and removal of objects of antiquity.
No person shall search for or remove from national wildlife refuges objects of antiquity except as may be authorized by 43 CFR part 3.
§27.63 Search for and removal of other valued objects.
(a) No person shall search for buried treasure, treasure trove, valuable semi-precious rocks, stones, or mineral specimens on national wildlife refuges unless authorized by permit or by provision of this subchapter C.
(b) Permits are required for archeological studies on national wildlife refuges in accordance with the provisions of this subchapter C.
Notice metal detectors is not specifically mentioned. And the same boiler plate stuff above could be said of BLM or NFS for instance, where it's not dis-allowed. Such that.... sure, so long as you're not looking for "treasure" (you're just looking for fumble fingers losses), and so long as you're not finding antiquities (50 or 100 yr. or older coins), then it's not dis-allowed.
Heck, the OP should be given a medal for removing potentially harmful metals that leach pollutants (lead, copper, etc...) that could harm the wild-life
Can you provide any citation (from your father or anyone) who has been "arrested" at a wildlife refuge for md'ing ? How is it that the OP, and people he saw (and myself and others) who've md'd them, never gotten hassled ? Oh sure, I'm sure that SOMEWHERE at one or a few of them, a "scram" has been passed out.
But the same could be said of city parks, beaches, etc.... of ANYWHERE we md'rs hunt, that anyone can gripe.