by Bryce W. Robinson
Recently I went birding with some friends at the Whitewater Preserve on the edge of the desert in southern California. My friend Dan Williams is more experienced with the birds in the area, and has a great ear. He picked up on something that I’ve been paying attention to since.
The Whitewater Preserve is located in an area that is the meeting point for the ranges of two very similar woodpeckers, the Ladder-backed and Nuttall’s. The Ladder-backed Woodpecker is a species of the southwest that frequents semi-arid landscapes. The Nuttall’s is a California coastal species, preferring riparian areas. Very similar in appearance and habits, it is easy to confuse the two when in an area where it is unclear which is expected, such as the transition zone between the two.
We heard a woodpecker fly overhead calling. Dan recognized the call as a Nuttall’s, but when it landed it resembled a Ladder-backed in appearance. This began my inquiry into the occurrence of hybridization in the region. I found many discussions on the topic, with no clear or definitive conclusion of how, if, or where this really occurs.
I returned later to the Whitewater preserve in hopes of recording and photographing as many woodpeckers as I was able. I failed, but I did get to know the woodpeckers of the region a bit better. I found many birds, and one female that supported the idea that these birds are hybridizing in the area.
Last night I went birding in the Big Morongo Preserve. It was great birding. The Summer Tanagers have returned in good numbers. I kept tuned to finding woodpeckers in this area, as it is not far from the Whitewater preserve. I finally found a male woodpecker, and sure enough, it showed characteristics of both species.
First, I heard the woodpecker. In my mind, it sounded just as the Ladder-backed Woodpeckers sound across the southwest, but when it landed, I noticed a few things that were unlike the Ladder-backed.
1. The Ladder-backed Woodpecker has striping that extends to its neck. The Nuttall’s has a patch of black on the top of its back. This bird resemble the Nuttall’s in this regard.
2. The male Ladder-backed has red on his crown that extends forward above the eye. The Nuttall’s red is less extensive, and sits on the back of the head. This bird resembles the Ladder-backed in this regards.
3. The Facial pattern of the Ladder-backed is dominated by white. The black markings are rather thin. The Nuttall’s facial pattern is dominated by black. Thick black lines swallow up the face. This bird is tricky, it looks much like a Nuttall’s, but the white above the eye and to the back of the head is rather prominent. I included an image of a Ladder-backed I photographed in Texas last month with a facial pattern much like the bird from Morongo.
There are other nuances separating the two species such as the pattern of the outer retrices, spotting or streaking on the flanks, cream color or white of the pale parts, bill shape, etc. All of these aspects are learned through exposure, in my mind. The more you see both species, the more you will recognize the minutia that separates the two.
If anyone stumbles on this post that has any information on the subject, knowledge, or experience with both birds, I would love to hear your ideas. In my mind, the evidence is fairly clear indicating that this bird is likely a hybrid, or cross back. That makes the possibility or regularity of this occurrence rather high in my mind. You just have to be in the right place. Or maybe I just got lucky.