Daily News Podcast
Daily Newsletters
116 3rd St SE
Cedar Rapids, Iowa 52401
Warblers on the move
Bird-watching: The palm warbler winters in the Caribbean, Yucatan Peninsula and in the far southeastern United States
As spring grows closer, a small group of wood warbler species will get a head start on migration, moving into Eastern Iowa from warmer areas to the south.
The majority of wood warbler species wait for the warmer south winds of May, which aid in their migration to breeding grounds in more northern latitudes. However, a select group of more “weather-hardy” wood warblers are picking their breeding spots much sooner.
Louisiana waterthrush, pine warbler, and yellow-rumped warbler are the earliest returners, although yellow-rumped overwinters in several locations throughout the state. Another 18 wood warbler species will eventually show up during the month of April.
The next cluster of earlier wood warbler migrants include northern parula, orange-crowned warbler, black-and-white warbler and the tail-bobbing palm warbler.
The palm warbler, Setophaga palmarum, is aptly named. It spends winters in the Caribbean, Yucatan Peninsula and in the far southeastern US. The core of its winter abundance is in Florida, the Bahamas and Cuba.
In early April, palm warblers begin their migration from wintering grounds to core breeding grounds in the boreal forests of Canada. They typically nest on the ground in peat moss. By mid-April, palm warblers will start to migrate through Iowa, with sightings petering out in late May.
During fall migration, palm warblers will begin to show up in small numbers in early September. By the end of September and early October, they are a fairly common migrant. Being “weather-hardy” really means they have a wider variety of food they can eat. Aside insects, they also can eat seeds and berries, which explains why November and even December records exist in Iowa.
There are two subspecies of palm Warbler. Iowa gets the “western” subspecies during migration. The other is the “yellow,” which migrates through roughly the eastern quarter of the country.
Palm warblers are one of the few warblers that prefer to forage on the ground. They will habitually bob their tails, a behavior that can greatly help to aid in their identification.
Iowa’s palm warblers shows a rich chestnut cap in the spring, with a yellow supercilium (eyebrow), brown auricular area (cheeks) and yellow throat. The backside is largely brown. Look for bright yellow undertail coverts, which show well in spring and fall. A light eyebrow and dark eyeline are good identification points in the fall. Of course, they should be tail-bobbing.
A singing palm warbler is not the easiest to identify nor commit to memory. There is really no melodic quality. It is identified as a short “buzzy trill,” similar to a chipping sparrow. While they forage low, males will sing up higher in trees.
During migration, look for palm warblers in weedy fields, along fence lines, along marshy edge habitat and in areas with scattered shrubs.
Birds of April
- Although waterfowl migration is past its prime in terms of numbers, April can be a great month of diversity. All five regular goose species still can be seen, although Ross’s and cackling geese get harder. Up to 20 duck species are regularly seen in Eastern Iowa throughout April.
- April is the best month for grebes. Pied-billed reach their peak numbers. Horned grebes can be seen in both breeding and non-breeding plumage. Red-necked and eared grebes are less common, but are findable. Some great semi-local places to look for grebes include Terry Trueblood RA, Amana Lily Lake, Cedar Lake and Pleasant Creek SRA.
- At least 27 species of shorebirds pass through Eastern Iowa in April. Many scope shorebirds to find rarer species. Two species that quickly peak in April are the godwits. The big pool at Hawkeye WMA is a great place to see sizable flocks of both hudsonian and marbled godwits. Sometimes these species will mix, which can make separating their identifications harder, especially as view distance increases.
- Most gull species are on the outs in April, but Franklin’s will peak in migration with strong numbers throughout the entire month.
- Common loon will peak in early April. Pleasant Creek SRA and Lake Macbride are two great places to seen loons lingering during spring migration.
- Large water-reliant birds like American white pelican, double-crested cormorant, great blue heron and great egret all reach impressive numbers in April. More notable, white-faced ibis peak in latter April.
- Broad-winged Hawk migration typically peaks in latter April. Keep an eye up to the sky and any kettles of raptors should be noted.
- Not many flycatchers are back in April, but eastern phoebe is one exception. Great crested flycatcher and eastern kingbird will start showing up in late April.
- April is typically the first month all five swallow species can be observed, plus purple martin. My mid-April it is not untypical to be able to see all six of these species hunting insects over ponds and small lakes.
- Golden-crowned kinglet will peak in early April, while ruby crowned will peak in late April to early May.
- Five wren species can be seen in April. House wrens will start to come back by mid-month. Winter, sedge, marsh and Carolina also can be seen.
- Hermit thrush peaks in migration in April.
- April has some of the best sparrow diversity. At least 18 species of regularly-occurring sparrows occur during the month.
- Eleven icterid species occur in April. The most beautiful migrant is probably the yellow-headed blackbird. Although this species can nest in Eastern Iowa, they typically nest more toward the northwestern quadrant of the state.
April calendar
- Warbler Walks at Hickory Hill Park, Iowa City, Monday through Friday, 6:30-8 a.m.: Walks are weekdays, starting April 26 and last until May 19. The walks are guided, with anywhere from one to three experienced guides on each walk. There are 24 to 27 species of warblers typically seen throughout the Warbler Walk season plus many more exciting species to see. Meet at the parking lot on the end of Conklin Lane, off North Dodge Street in Iowa City. Daily results are posted on the Iowa City Bird Club website and Facebook page. Non-members welcome.
Brandon Caswell has a keen interest in natural and social sciences. He enjoys bird-watching and nature photography in his spare time. He and his wife live in Marion with their two children.
A “western” palm warbler forages among leaf buds at Hawkeye Wildlife Management Aarea Swan Lake in late April. This subspecies is much less yellow overall compared to the “yellow” subspecies found more eastward. (Brandon Caswell/correspondent)
A pair of palm warblers interacting in late April. This photo was taken near Nichols in Muscatine County near the Cedar River. (Brandon Caswell/correspondent)
A black-and-white warbler inspects a water feature at Estero Llano Grande State Park in Hidalgo County, Texas, in early April. This species will start to show up in Eastern Iowa early- to mid-April. (Brandon Caswell/correspondent)
Northern [arula will start singing in early to mid-April in Eastern Iowa. Listen to their buzzy song, which ascends up to a sharp ending chip. This adult male was seen in early April at Estero Llano Grande State Park, Hidalgo County, Texas. (Brandon Caswell/correspondent)
A flock of hudsonian godwits feeds in the shallow areas at the northeast corner of Hawkeye WMA in Johnson County in mid-April. Note that the larger, lighter godwits are females. The males are smaller and have chestnut-colored bellies. (Brandon Caswell/correspondent)
