Molt: (of birds, insects, reptiles, etc.) to cast or shed the feathers, skin, or the like, that will be replaced by a new growth. While it is something we are well aware of, molt is a highly complex part of a bird’s life history. There are many questions about why, when, how, where birds molt. Steve N. G. Howell’s Peterson Reference Guide to Molt in North American Birds aims to answer these in a complete and highly scientific reference.
With a large array of photographs accompanying detailed (and technical) text, Molt explains the ins and outs of molt strategies among North American bird families that occur north of Mexico. Topics ranging from the evolution of molt strategies to how plumage is colored is covered. Also included are diagrams labeling the types of feathers on various bird families (primaries, secondaries, scapulars, tertials, etc.).
Molt describes the four fundamental molt strategies:
- Simple Basic Strategy (SBS)
- Complex Basic Strategy (CBS)
- Simple Alternate Strategy (SAS)
- Complex Alternate Strategy (CAS)
Howell also goes into how molt can be a critical tool when identifying difficult and closely-related birds in the field. Of course, in many birds molt is not going to be the best key for identification, but having a good basic understanding of how molt works is still valuable for even casual birders.
Molting patterns assist in life-history predictions such as migration distance and breeding seasons. Howell explains how information about Black Swifts and Cave Swallows, for example, have been unearthed because of studying molt. And while a lot of molt is easier to witness in birds captured (either collected or in bird banding), birders can witness molt in the field with careful observations and knowing what to look for.
For the average birder, Molt may be a bit much to digest and surely isn’t the easiest of reads. The science behind it is complex although utterly fascinating. But Howell provides a great reference to study specific bird families or to look up information that has much more complete coverage than other bird books.
The large introduction is especially worthwhile if you can survive it. (I was never good at the more scientific aspects of birding, the reason I got a degree in marketing after switching majors from biology.) The individual sections on families of birds provides some great points especially in commonly hard-to-identify groups like wood-warblers and sparrows.
The book was sent to us by the publisher to review and the links are Amazon affiliate links.