It’s obvious at even the most cursory examination. Jeanson writes:
[I]n chapter 6 of Replacing Darwin , I walked the reader through very detailed calculations on what the rates of speciation might be. Since mammals are familiar to most people, I focused on the numbers for these types of creatures. Applying these calculations to birds, we can predict the rate at which new species should form.
This should be our first red flag. A quick skim of this paragraph would leave the reader with the impression that Replacing Darwin predicted bird speciation rates, but closer examination reveals otherwise. He says that in Replacing Darwin he predicted speciation rates for mammals and that he is merely applying the same calculation to birds now. Any time that you are making “predictions” after the evidence you are claiming confirms your predictions, there’s a problem.
[I]n birds, about 11,000 recognized species exist. If birds formed new species at a constant rate over 4,500 years, then on average about 2.4 new species should form every year (11,000 species / 4,500 years = 2.4 species per year). […] As long as the long-term average is 2.4 new species per year, either of these ways is consistent with the YEC timescale. Both of these ways lead to predictions that we can test.
We have two more problems here. First of all, we are making predictions after the fact. If he could have predicted the Darwin hybrid speciation “rates” then why didn’t he? You can’t come along after a discovery and rework your math and say “See, this is what we would have predicted if we had known to predict it!”
Second, and more fundamental…where is he getting this 11,000 number from? Does he believe there was only one “bird kind” pair on board the Ark? IIRC, AiG claims something like 40 different bird “kinds” representing all extant species, so we would be starting not at 1 but at 40. What about the thousands of fossil bird genera? Why is his calculation linear? If he is advancing created heterozygosity, where a population splits into two, then he would need to say that 40 kinds became 80 sub-kinds which became 160 sub-sub-kinds and so forth, exponentially. He doesn’t say that, of course, because that would imply that we would be seeing the fastest speciation rates now of any time at history.
His only purpose in choosing to use these numbers is to come up with a post hoc prediction which appears to be close to the numbers he will later fudge from the actual science research.
And that’s not even dealing with the bigger problem, that hybridization speciation (if that’s in fact what happened with these finches) is a different type of speciation event than the created-heterozygosity-speciation he proposes. You can’t have hybridization speciation unless you already have two separate species to hybridize.