Northern Flickers: Red-shafted, Yellow-shafted, Whatever
(Blending Biomes and Transitional Taxonomy)
Dr. James J. S. Johnson
But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. (Acts 1:8)
Was that a Red-shafted Flicker, or a Yellow-shafted Flicker, or a mix of them?
(Regarding Northern Flickers in Colorado, see “Want a Home in the Mountains? Some Birds Have One”, posted at https://leesbird.com/2015/09/24/want-a-home-in-the-mountains-some-birds-have-one/– the discussion notes the difference between the “Red-shafted” and “Yellow-shafted” varieties.)
Hybrids don’t fit squarely into the category boxes that we use for convenience. The missionary mandate of Acts 1:8, given by the resurrected Christ, refers to outreach—to Jews and Gentiles, and a hybrid category: Samaritans. In effect, Samaritans were a hybrid people, part Jew and part Gentile.
That reminds me of how birdwatching has its own taxonomy challenges, when “splitters” are forced to yield to “lumpers”, especially in transitional habitats.
Have you ever seen a bird that looks partially like a particular subspecies, yet also like its “cousin” subspecies? Maybe you were looking at a hybrid. After all, avian subspecies have shared ancestries, tracing back (through the Ark) to Day # 5 of Creation Week (Genesis 1:21).
When a gene pool is separated by geographic barriers the foreseeable result is geography-correlated phenotype pattern, illustrating recessive genes within the geographically isolated gene pool. Breaks in such geographic barriers, however, provide for transitional blending — of both biome-based habitats and of the communities of animals that inhabit those regions. These “border” zones are sometimes called ecotones: expect to see (there) blended gene pool patterns.
“An ecotone is a boundary area between two kinds of habitats, or ecosystems. The transition between eastern deciduous forest and Great Plains prairie grassland forms one of the broadest and geographically largest ecotones in North America. The separation between forest and prairie is a gradual one. Remnant patches of prairie exist in Mississippi, Ohio, Indiana, Illinois, Wisconsin, Minnesota, and other states, extending into southern Manitoba. The farthest route of penetration of eastern deciduous forest into the west is provided by rivers: the mighty Platte, Missouri, and Arkansas Rivers, and their many tributaries. The forests that line these rivers usually flood in the spring when [snow-fed] meltwater brings the river to crest. The floods are followed by summer drought, when evaporation tends to exceed precipitation, and the water level drops. Because of this annual cycle, western riparian forests tend to have broad, fertile floodplains, where sediment is deposited as waters recede. ….
For the birder, the prairie riparian forest offers a unique mixture of eastern and western species and subspecies. Both Rose-breasted and Black-headed grosbeaks may be encountered in the same cottonwood grove [although usually the Rose-breasted Grosbeak lives in Eastern forests, while the Black-headed Grosbeak lives in Western forests]. Indigo and Lazuli buntings may sing from willows on opposite sides of a river [although usually the Indigo Bunting lives in Eastern forests, while the Lazuli Bunting lives in Western forests]. Eastern and Western kingbirds may sit side by side on utility wires. A pendulous oriole’s nest may be inhabited by a pair of the [Western forest] “Bullock’s” subspecies of Northern Oriole, or a pair of the [Eastern forest] “Baltimore” subspecies—or a female “Baltimore” and male “Bullock’s”! A Northern Flicker may prove to be a member of the [Western forest] “Red-shafted” subspecies, the [Eastern forest] “Yellow-shafted” subspecies, or a hybrid between them.”
[Quoting John C. Kricher, A FIELD GUIDE TO THE ECOLOGY OF WESTERN FORESTS (Houghton Mifflin,1993), pages 88-90.]
So, if you want to challenge your birdwatching taxonomy skills, go visit an ecotone — an don’t be surprised if you see a hybrid version of some bird that is otherwise known of regional subspecies. It’s all about geographic barriers to the gene pool — if the birds can mix the birds can mate, assuming they all descend (biogenetically) from the same ancestors created by God on Day # 5!