Dipper birds are quite special birds in that they are the only known species of passerine bird (songbird) that is semi-aquatic in the Americas, relying almost entirely on water to supply their food sources of aquatic insects and larvae, crustaceans, and small fish. In fact, dippers are named for the way that they rapidly dip their heads in and out of water when searching for and catching prey!
There are five dipper species, all contained in the genus Cinclus, the only genus in the Cinclidae (dipper) family. They include the American dipper (sometimes called the water ouzel) of the Americas, the brown dipper of the eastern Palearctic region, the white-capped dipper of South America (primarily within the Andes mountains), the rufous-throated dipper of the southern Andes, and the white-throated dipper (also known as the European dipper) of Europe, the Middle East, portions of central Asia, and the Indian subcontinent of southern Asia.
There are also dozens of subspecies, which can be quite difficult to identify unless one is an ornithologist or very avid birder. The American dipper alone has five subspecies, all native to various regions of South, Central, and North America. These are largely differentiated by minute differences in color, but DNA testing has confirmed them to all be different, albeit very closely related, species branching off from the American dipper.
Interesting American Dipper Facts
These interesting, jovial little birds can not only fly and swim, but they have surprisingly strong and sturdy legs despite their rather dainty appearance, equipped with long, highly tensile toes and claws that allow them to expertly grip just about anything. Because of this, dippers can appear to walk underwater even in fast-flowing rivers and streams!
What’s more: dippers, including C. mexicanus, have double the average number of feathers for a bird their size to increase both insulation and swim speed, specially adapted iris muscles that enable them to see underwater as well as above, high concentrations of hemoglobin that allow for superior blood flow and muscle function even in frigid mountain air and waters, and many other adaptations that allow them to live their unusual, high altitude aquatic lifestyle year-round without needing to migrate.
They’re an overall chipper (we had to!) group of birds, with John Muir noting how gleeful they are even in the midst of winter storms whilst other birds are taking shelter, or when diving through crashing waterfalls in Yellowstone National Park. Because of their charm and exceptionally unique adaptations, American dippers became one of John Muir’s favorite and most sought-after bird species and are still highly sought after by many as it can be hard to find them as they flit about quickly or stay underwater for periods of time and blend in rather well.
American Dipper Native Habitat & Range
American dippers can be found largely throughout the western Americas, ranging broadly from as far south as Panama to as far north as Alaska. The subspecies C. m. unicolor can be found in Alaska and throughout the western contiguous U.S. as well as western Canada. The subspecies C. m. mexicanus is found exclusively in central and northern Mexico. The subspecies C. m. anthonyi has a bit more of a patchy distribution, inhabiting southeast Mexico, southwest Guatemala, east Honduras, and northwest Nicaragua. Southern Mexico makes up the range of the subspecies C. m. dickermani, while the last American dipper subspecies, C. m. ardesiacus, can be found throughout Costa Rica and the western regions of Panama.
As with all dipper species, you can expect to find American dippers in and along fast-flowing streams and rivers with ample water movement and rocks and rocky substrate suitable for the aquatic insect species that they depend on. They can be found along slower-moving waters at times, as well, and along some lowland coastlines outside of the nesting season. Often, dippers greatly prefer mountainous and cliff-like habitats, found almost exclusively in these types of areas during the nesting season. Steep and rocky terrain help protect their eggs and young from potential predators, while nearby (usually directly below or adjacent to the nesting area) rivers and streams provide ample food. They may also be found along lakes and ponds that are fed by rivers or streams, and lowland habitats like grasslands and wetlands during winter when upland water sources have frozen.
The water must be clean and well-oxygenated, as this provides the most suitable habitat for the largest number of aquatic insects and fish alike, both of which dippers depend on. Polluted waters often result in dippers moving from the area within just a season or two as pollution and low-oxygen conditions greatly diminish the availability and health of their prey.
American Dipper Identification & Appearance
American dippers, regardless of gender, average about 16.5 cm (or 6.5 inches) in length but can be as short as 13 cm and as long as 17 cm. Males and females are similar sizes overall, with significant weight overlap. Males are typically between 50 and 61 grams while females often weigh between 44 and 59 grams. These birds are fairly small and appear rather round, due partially to their massive amount of dense feathers meant to both keep them warm, keep water out, and hold air bubbles to enable faster swimming (much like the feathers of penguins do). In fact, all dipper species have around 6,000 feathers – compare this to the similarly-sized robin, which has only 3,000!
Adult plumage is almost exclusively medium to dark grey, sometimes with grey-brown throat and head plumage. Their eyelids are white, much like the white-throated dipper. Though not known with certainty, many believe that these eyelids serve as a method of communication. Since dippers are primarily found in or near rushing water, it’s quite possible that they are unable to hear one another’s calls very well even if in close proximity. The flash of eyelids could function as a means of passing on information and warnings to other dippers.
American Dipper Diet & Nutrition
Dippers, including American dippers, feed almost exclusively on aquatic insects and their larvae like mayflies, midges, and mosquitoes, but will also eat the occasional small fish, fish eggs, worms, and small crustaceans. They can be observed obtaining food by diving into the water, walking along the water’s bottom, or even swimming through strong currents! They rely on heavy amounts of protein to fuel their very active, non-migratory, year-round lifestyle that persists through even the harshest of winters.
American Dipper Behavioral Traits
Perhaps the most notable behavioral trait of all dippers is their namesake – when searching for food, they very quickly dip their heads in and out of the water (as much as 60 times per minute!). They will often perch on rocks in the water or wade directly in the water to do this, sometimes gripping small stones beneath the water, as well. Male dippers will also dip and bob their heads to attract females as well as warn off other males.
To attract females, males will puff out their chests as they sing various songs, alternating between singing and flying in daring patterns, often flying high, swooping and plunging low, and repeating the process to showcase their physical prowess. American dipper females seem to choose males primarily based on song, while European dippers utilize the flight patterns and songs a bit more equally when choosing.
Additionally, as mentioned previously, American dippers possess white eyelids that flash noticeably when they blink. It is believed that this is for the sake of communicating with other dippers, as it can be quite difficult to hear calls and songs over the rushing rivers that these small birds are most often found in and near. Some ornithologists believe that this is also why dippers bob up and down so much, to further aid in communication in such noisy environments.
American Dipper Reproduction Habits
American dippers are largely monogamous, typically keeping the same mate for several breeding seasons and utilizing the same nest or approximate nest location each year as breeding pairs maintain a territory for their entire lives, if possible. Sexual maturity is reached somewhere around one year of age.
The male and female both contribute to building and guarding the nest, which is usually placed very near a river, often in hard-to-reach, steep rocky crags and cracks. Dipper nests have also been found on bridges, in tree cavities (rather more uncommon), on rocky ledges or large rocks themselves, and even behind waterfalls!
Dipper nests are large and round, often resembling a basketball in both shape and size. They can be quite elaborate, often containing two chambers but sometimes only containing one. The outer chamber is made mostly of moss (which, it has been observed, can and often is dunked in water to further insulate it), serving the primary purpose of insulation from the elements and protection from prying eyes. The inner “cup,” if there is one, is made of moss, grasses, leaves, and sometimes feathers and fur. Occasionally the two layers may be offset from one another with separate entrances to make it more difficult for predators to see or get to eggs and chicks. Usually, the entrance faces the water. It is rather more common for American dippers to create two-chambered nests than other dipper species.
The average brood size for American dippers is four to five eggs, and dippers can have up to two broods per year if weather and resources permit. The female incubates the eggs, while the male helps by bringing her food. After approximately two weeks, the eggs hatch and both parents contribute to feeding and guarding. After another 20 to 25 days, most young have fledged but stick around the vicinity for another week or so before becoming fully independent.
Some parents may continue feeding their young for a couple of weeks after they’ve fledged, though this isn’t known to be incredibly common. Wild American dippers can live up to seven years if they’re able to obtain enough resources, survive tough seasons, and avoid predators and other threats such as water pollution.
American Dipper Population Threats & Numbers
Though American dippers are listed as “Least Concern” by the IUCN Red List, they have a global adult population of just 160,000 birds, with this number decreasing by approximately .4% per year. Though this decrease isn’t quite alarming, it does mean that we must be vigilant in helping to protect these very unique (and historically significant!) birds from further losses.
The greatest threats to American dippers are decreasing water quality due to pollution, reduced insect populations due to various human impacts like ecosystem destruction and pollution, and dipper habitat loss through human expansion and development. Dams and similar impoundments built along rivers greatly alter and remove dipper habitats, and even irrigation and hydro-electric operations diminish habitats as they significantly reduce water flow, thereby affecting dippers by decreasing food populations, like those of various aquatic insects as well as fishes that they depend on.
One study explored multiple shifting environmental factors within watersheds containing American dippers, such as land-use changes due to humans and climate shifts. Though the authors acknowledged that more research is needed, they found that American dippers are quite sensitive to shifts in water quality and overall stream and river conditions (such as water levels). This means that one of the greatest threats facing American dippers, like so many other species, is climate change as abnormal periods of drought affect more and more watersheds that these birds depend on for survival. Additionally, altered water conditions similarly impact the aquatic invertebrates that dippers feed on.
However, this study does point to a silver lining: American dippers’ sensitivity to changes like these makes them incredibly valuable to study as bioindicators of stream health and water quality! As some of the first species to respond to adverse conditions, we can more quickly gauge when an area is experiencing issues by observing dippers and thus can respond accordingly by doing things such as improving water quality, creating macroinvertebrate habitats, avoiding taking water from these streams, and so on to help not just the dippers, but the entire watershed of the particular area.
