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Introduction
There seems to be a plethora of black-and-white woodpeckers in North America! Some have specialized, some have diverged, and some still look like each other. Nuttall’s woodpecker is another one of these confusing similar-looking species, and yet surprisingly, their habitat association is the most researched part of their biology. Sometimes it can be easy to overlook relatively common species in your backyard – though in this case, your backyard would have to be California west of the Sierra Nevada mountains and the Cascades – and it may be that Nuttall’s woodpecker is an underappreciated and understudied member of that avian community. As a biologist, I think these zebra-backed birds are pretty interesting, especially considering their population seems to be doing well even though they have a relatively small range and fairly specific habitat requirements. Let’s find out what’s known about them!
Bottom Line Up Front
Nuttall’s woodpecker has a restricted range, as they are only found in parts of California and Baja California, where they prefer oaks and consume a range of insects, fruits, and berries, but will come to backyard feeders if suitable habitat is nearby. By excavating cavities they provide nesting places for many other species. This black-and-white woodpecker really is black-and-white all over, and will even breed with the similar-looking black-backed woodpecker in the small range of overlap.
Taxonomy
This species was named after Thomas Nuttall, a British naturalist, in 1843. The genus name, Dryobates, means ‘woodland walker’.
Their closest relative is the ladder-backed woodpecker (D. scalaris), and they look quite similar; in fact, they have been known to hybridize. The red-cockaded, downy, and hairy woodpeckers also have similar plumage, though the downy woodpecker (D. pubescens) is the only one of those in the same genus (and so is more closely related). There are occasional reports of hybridization with downy woodpeckers as well. Below I describe how to tell all these species apart.
How to Identify Nuttall’s Woodpecker
Nuttall’s woodpecker are basically black and white all over. From a head with two black stripes (or two white, depending on which you want to count), to a black and white spotted back that blends into their black and white spotted wings, to white flanks with black spotting, to a black tail with mainly white outer feathers, they are a zebra-striped bird pretty much all over. The only spot of color is on the crown – males have a red crown, whereas females do not, and juveniles may have a smaller red patch on their head.
Their length is 16-18 cm, and their mass is 30-45 g. There is slight sexual dimorphism; females have slightly longer tails (but it’s a small difference, about 1-1.5%), while males have slightly longer wings (by 0.5-0.6%) and bills (by 8%) and are heavier (by 2-3%). These small differences mean it’s unlikely you can tell by size alone which is a male and which is a female; look for the red crown patch instead.
Nuttall’s woodpecker looks very similar to the closely-related ladder-backed woodpecker. The ranges of Nuttall’s and ladder-backed woodpeckers barely overlap, so the easiest way to tell them apart is to know which species is present in the area you are in. In some locations, they breed within a couple of kilometers of each other (a distribution called ‘parapatry’), and in one location (which is in Baja, California) there is a zone where they overlap completely (called ‘sympatry’). If you happen to be in the overlap zone, here is what you should look for:
- on the side of the head, Nuttall’s woodpecker has narrower white stripes than black stripes, whereas the ladder-backed woodpecker has dark and white stripes that are about equal width
- in males, the red in Nuttall’s woodpecker crown is only on the back of the head, whereas the red on the ladder-backed woodpecker extends further forward on the head
- the outer tail feathers have only a few black bars in Nuttall’s woodpecker, whereas they are fully barred in the ladder-backed woodpecker
- the bill of Nuttall’s woodpecker is shorter than that of the ladder-backed woodpecker
Basically, the Nuttall’s woodpecker has more black overall in its feathers, and the ladder-backed woodpecker has more white. Unless you have a lot of practice or are familiar with one species, however, this relative difference may be tricky to spot if you only see one bird.
Their calls are another way to distinguish them. Nuttall’s woodpecker will make a call like a low rattle, while ladder-backed woodpeckers only make the more typical short pik. The drumming of the two species also differs. Nuttall’s have a drum of 19.6 beats/sec, and ladder-backed have a drum of 30 beats/sec.
The similar-looking downy and hairy woodpeckers have a white stripe down their back and white flanks, whereas Nuttall’s woodpecker has a striped back and barred flanks. The red-cockaded woodpecker looks similar to Nuttall’s woodpecker as well, but their ranges are entirely separate – Nuttall’s is only in the state of California and Baja California, whereas red-cockaded is only in the southeast of the US, and so the location will always give you the correct species.
Where Does Nuttall’s Woodpecker Live: Habitat
They predominantly use oaks, but will also use pines, and are found in riparian willow-cottonwood-sycamore woodlands when oaks are scarce, mainly in the south part of their range. Nuttall’s woodpeckers will shift their trees of preference during the year: during breeding they use blue oaks, whereas during the winter they prefer live oaks. Because they create new nest cavities each year, they are a keystone species in oak woodlands, supporting the abundance of many other species of cavity-nesting birds.
Nuttall’s Woodpecker Diet and Feeding
They often take insect prey from surfaces and cracks by probing and gleaning, and also scale back bark searching for bark beetle larvae. They also eat berries and fruits, will lick sap when present, and consume true bugs and caterpillars gleaned from bushes and shrubs.
Males and females forage slightly differently, with females foraging higher in trees and on smaller branches by gleaning, while males were seen lower on trees and used tapping (soft blows to widen crevices) more often.
Nuttall’s Woodpecker Breeding
Males are aggressive towards other males especially during breeding, using drums, calls, and visual displays to ward off rivals. Pair bonds may last several years, which may be helped by the fact that they are year-round residents on their territories. Adults within territories are fairly solitary from late summer to winter, then pairs forage together more often in late winter, courting and reinforcing pair bonds. Pairs use contact calls, described as ‘sucking’ or ‘wheezing’ calls, to identify each other. Drumming by males increases in late winter. Copulation occurs after the nest is completed, with a kweek call used by the female towards the male before copulation
Nuttall’s Woodpecker Nesting
They can nest from late March to mid-June. Males pick the nest site and excavate the nest cavity, and the cavities are not reused. Females assist in making the cavity at the very end of construction. The average entry diameter is 5 cm. Nest site competition may be high, as Nuttall’s woodpecker experience aggressive interactions with several other woodpecker species and passerines during this time. This may indicate that appropriately decayed trees have limited availability, and highlights the value of woodpeckers that create nesting cavities for use by other obligate cavity species in subsequent years.
Nuttall’s Woodpecker Eggs
They lay 3-6 white eggs, usually 4-5, one clutch per year. Males incubate at night, and both sexes incubate during the day; the same pattern was observed for brooding the young. It is unknown why males do the night incubating and brooding. Both sexes feed the nestlings. There is very little information on some of these details; the single nest recorded in the literature indicated incubation was at least 14 days, and the young fledged after 15 days.
Nuttall’s Woodpecker Population
This species is non-migratory. Their range is almost entirely within the state of California; it also extends into Baja California. They have occasionally been reported in Oregon and Nevada.
Nuttall’s Woodpecker Endangered?
No, they are listed as Least Concern. Despite having a fairly small range, their population seems stable and is currently estimated at 850,000 individuals. Anything that degrades oak woodlands will harm their population.
Nuttall’s Woodpecker Habits
Nuttall’s woodpecker has been known to give several different types of vocalizations: pik, pitit, rattle, kweek, wicka, and twitter. A pik is the most common contact call; pitit is the most distinctive of the species and may be used for contact or threat; rattle is a series of pik notes that get slower and raspier at the end; kweek is used by the female before copulation; wicka is a series of high-pitched rising and falling notes; and twitter is usually three high-pitched notes used during aggressive interactions.
They also use many visual signals, including bill pointing, crest raising (mainly by males towards other males), head bobbing and swinging, wing flicking and spreading, tail spreading, and direct attacks.
Nuttall’s Woodpecker Predators
A pygmy owl was reported to take a Nuttall’s woodpecker; there are no other records, but it is likely that other avian predators within their range would also be sources of mortality.
Nuttall’s Woodpecker Lifespan
The oldest individual was 8 years 9 months old when she was recaptured, as determined by her band information.
FAQs
Answer: You need to go to California. Next, find some oak woodlands; these birds are usually fairly visible, but remember to look in shrubs too, as they will often forage there. You can also put up a suet feeder, as these birds will visit urban areas if there are oak woodlands nearby.
Answer: Surprisingly, none. Despite this species being strongly associated with oaks, they do not consume acorns.
Answer: He was an English botanist and zoologist who lived from 1786-1859, spending part of his life (1808-1841) in America. He has two other birds named after him (the yellow-billed magpie, Pica nuttalli, and the common poorwill, Phalaenoptilus nuttallii), 44 marine species, and at least 7 species of plants. The Nuttall Ornithological Club, founded in 1873, was also named after him.
Conclusion
Like other species, some aspects of Nuttall’s woodpecker life history and ecology is well known, while other parts are still lacking or data is derived from preliminary studies. For a species with a relatively small range that is fairly heavily dependent on a particular ecosystem, it’s a little surprising that more is not known about some of their basic biology. The evolutionary ecologist part of myself wants to know so much more than that – like, how much do aggressive interactions drive their narrow zone of sympatry with the similar ladder-backed woodpecker? Are colours and/or song diverging to reduce hybridization? What adaptations make these birds prefer mesic woodlands, while closely-related species inhabit xeric deserts? This species presents a rich body of questions to still be addressed, in addition to being an easily-observable bird that urban Californians can find as well.
Research Citations
- Block, W. M. (1991). Foraging ecology of Nuttall’s woodpecker. The Auk, 108(2), 303-317.
- Browning, M. R., & Cross, S. P. (1995). Third specimen of Nuttall’s woodpecker (Picoides nuttallii) in Oregon from Jackson County and comments on earlier records. Oregon Birds, 20(4), 119-120.
- Houck, W.J., Blackford, J.L., Morley, A.G., Sams, J.R., Gates, J.M., Harvey, H.T., Brock, E.M., Bohl, W.H., Gordon, S.P., Sick, H. and Lanyon, W.E., 1958. From Field and Study. Condor, pp.337-341.
- Jenkins, J. M. (1979). Foraging behavior of male and female Nuttall Woodpeckers. The Auk, 96(2), 418-420.
- Lowther, P. E., P. Pyle, and M. A. Patten (2020). Nuttall’s Woodpecker (Dryobates nuttallii), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.nutwoo.01
- Manthey, J. D., Boissinot, S., & Moyle, R. G. (2019). Biodiversity genomics of North American Dryobates woodpeckers reveals little gene flow across the D. nuttallii x D. scalaris contact zone. The Auk: Ornithological Advances, 136(2), ukz015.
- Miller, A. H., & Bock, C. E. (1972). Natural history of the Nuttall Woodpecker at the Hastings Reservation. The Condor, 74(3), 284-294.
- Purcell, K. L. (2011). Long-term avian research at the San Joaquin Experimental Range: Recommendations for monitoring and managing oak woodlands. Forest ecology and management, 262(1), 12-19.
- Short, L. L. (1970). Reversed sexual dimorphism in tail length and foraging differences in woodpeckers. Bird-banding, 41(2), 85-92.
- Short, L. L. (1971). Systematics and behavior of some North American woodpeckers, genus Picoides (Aves). Bulletin of the AMNH; v. 145, article 1.
- Stark, R. D. (2002). An analysis of eastern Nearctic woodpecker drums (Doctoral dissertation, The Ohio State University).
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