Cardinals are a common sight in Hawaii, where they have become a well-established part of the islands’ avifauna. These bright songbirds are frequently seen across the archipelago, bringing a flash of color to parks, gardens, and suburban areas. However, these birds are not native to Hawaii; their presence is a direct result of human introduction.
The Two Cardinal Species Present
Visitors to Hawaii are likely to encounter two distinct species that share the common name “cardinal.” The Northern Cardinal (Cardinalis cardinalis) is native to North and Central America. The male is instantly recognizable by its brilliant red plumage covering its entire body, contrasted by a black mask around its bright red bill. The female is a more subdued brownish color, featuring a reddish tint on its crest, wings, and tail.
The Red-crested Cardinal (Paroaria coronata) originates from South America. This bird presents a strikingly different appearance, with a prominent, bright red crest, head, and throat. The rest of its body is primarily dark gray on the back and wings, with clean white underparts and a whitish collar separating the red throat from the gray back. Unlike its northern counterpart, the male and female have nearly identical plumage.
How Cardinals Arrived in Hawaii
Neither the Northern Cardinal nor the Red-crested Cardinal arrived in Hawaii through natural migration. Both species were intentionally introduced to the islands in the late 1920s and early 1930s by various acclimatization societies and bird enthusiasts. These groups sought to enrich the local bird population by importing ornamental species from around the world.
The Northern Cardinal was introduced starting around 1929, with hundreds of birds shipped from the mainland United States, primarily from California, and released on several major islands. The Red-crested Cardinal, native to countries like Brazil and Argentina, was also released between 1928 and 1931. These introductions were carried out to establish populations of attractive cage birds within the Hawaiian landscape. These deliberate releases allowed both species to quickly establish self-sustaining populations.
Distribution and Habitat in the Islands
The two cardinal species have successfully colonized all the main Hawaiian Islands, including O‘ahu, Maui, Kaua‘i, and Hawai‘i Island. They are most commonly found in low-elevation, disturbed habitats near human habitation, such as urban parks, residential gardens, agricultural fields, and open scrublands.
The Red-crested Cardinal favors drier, open lowland areas and beach parks, typically remaining below 400 meters in elevation. The Northern Cardinal is also widely distributed in these human-altered landscapes, often thriving in gardens and lowland forests with a dense understory. Both species are significantly more concentrated in the lower, developed zones where non-native plants and food sources are plentiful.
Ecological Status and Impact
The Northern and Red-crested Cardinals are classified as non-native species in Hawaii’s isolated ecosystem. Their establishment reflects their adaptability to the tropical climate and the modified habitats prevalent across the islands. The presence of these introduced birds results in competition with native Hawaiian avifauna for limited resources.
These cardinals forage on the ground for seeds and insects, placing them in direct competition with native seed-eaters. They also use available nesting sites, which reduces resources for native forest birds. Furthermore, their diet includes the fruits and seeds of many non-native plants, meaning they contribute to the dispersal and spread of invasive vegetation across the islands.