I was asked to examine the recordings and photos of the meadowlark at Bud Mielke Reservoir in May 2020. The call notes definitively rule out Western Meadowlark, and the songs and (poor) photos are consistent with Chihuahuan, so in my opinion that bird can safely be called a Chihuahuan Meadowlark.
By contrast, the meadowlark at Heil Valley Ranch in Boulder earlier this summer had 100% Western Meadowlark plumage, even though it sang only Chihuahuan Meadowlark songs. It's not uncommon for the three meadowlark species to learn each other's songs, so song alone is not sufficient to identify them. If you are hearing a bird that sounds like a Chihuahuan Meadowlark, you'll need recordings of the "dzert" call and/or good photos of the bird (the face and, especially, the spread tail) in order to rule out the other two species.
Nathan Pieplow
Boulder