PAUL B. HAMEL

Fauwtte azude, ParulineFRENCH: azude Cerulean SPANISH: Bijirita azulosa (Cuba), Verdin an&do, Gorjeador ceruleo, Chipe Warbler ceruleO (Mexico). ._ Reinita certileA (Venezuela) Dendroica cerulea

his small, canopy-foraging insectivore breeds locally in mature and older Tdeciduous forests with broken canopies across much of the eastern United States. Sky blue, sky high in the canopy, the Cerulean Warbler has been little studied; management actions to enhance its habitat have not yet been specified. Among Dendroicu, this species for- ages and nests higher in the canopy, and

migrates farther and earlier, than most others. 0 Brian E. Small Its social system remains poorly understood. Numerous interesting questions about winter- ing individuals in montane South American forests, where this species associates with others in mixed flocks of canopy insectivores, await investigation. Although the Cerulean Warbler was form- erly among the most abundant breeding warblers in the Ohio and Mississippi River valleys, its numbers r&.unmeted in the 1900s. Concern for the future of this species is warranted. The Yet even in the face of these Birds of steep declines, some pop- ulations are currently ex- North panding. Several independent Ame.rica teams have investigated Life Histories for this warbler on its breed- the 21st Century ing grounds: in southern Illinois, by the Illinois Natural History Survey, principally Scott Robinson (Vanderah and Robinson 1995); in the Cumberland Plateau, by the University Figurel. of Tennessee (Knoxville), principally David Bleeding distribution oi the Car&an Warbler. This species Buehler and Charles Nicholson (Nicholson and winters in South America. %a text for details. Adapted and modified from Dunn and Garrett 1997. Buehler 1998); southern Ontario, by scientists at Queen’s University, principally Raleigh Robertson (Oliarnyk 1996; Oliarnyk and Robertson 1996; Jones and Robertson 1997,1998); and in the lower Missis- sippi Alluvial Valley, by scientists at the USDA Forest Breeding range. Following description based on Service, Southern Hardwoods Lab, principally the Dunn and Garrett 1997, except as noted. Breeds mainly author. Progress reports on the work of these groups from central Minnesota, n. Wisconsin, the central Lower were combined in a 1998 symposium (Hamel 1998a). Peninsula of Michigan (locally in W.-central Upper Peninsula of Michigan), s. Ontario (north to about 44.30”N; Eagles 19871, New York (including Long I. but absent from Adirondack Mtn. region), Connecti- cut, and RhodeIsland, south through nw. New Jersey, Small wood-warbler (11.5 cm, 8-10 g) with relatively Pennsylvania, extremen. Delaware, and the mountains long, pointed wings and short tail with long under- of w. Virginia, w. North Carolina, and extreme ne. tail-coverts. Adult male deep cerulean blue above, Georgia, and west to central Arkansas, Missouri, and white below, with a narrow blue-black band across e. and central Iowa. Within this area, not uniformly the throat. Adult female bluish green above, white distributed; breeding more widespread within some washed with yellow below, with a distinct white or areas (e.g., s. Missouri, s. Wisconsin, e. Kentucky, W. yellowish line over the eye. Both sexes in all plumages Virginia, e. Ohio), while extremely local in other areas have 2 white wing-bars and white tail-spots. Males (e.g., Illinois, n. Indiana, w. Tennessee, w. Kentucky). have streaked backs in all plumages; females do not. Local breeding also extends north to extremes. Quebec Seasonal variation in adult plumage is less than that (north to about 45.30’N; Bannon and Robert 1996), among individuals. Some fall males show greenish w. Vermont, central Massachusetts; east to e. Virginia edges to back feathers. First-fall (Basic I plumage) in- and e. North Carolina; south ton. Alabama, s. Arkansas, dividuals are similar to adult female in general appear- and possibly n. Mississippi (Turcotte and Watts 1999); ance, with upperparts gray-green to olive (female) or and west to easternmost portions of Oklahoma, Kan- bluish to blue-gray washed with green (male), prom- sas, and Nebraska, and possibly se. South Dakota inent pale superciliary stripe, dark ear-coverts, dull (Peterson 1995). May also breed in n. Louisiana and whitish underparts, and 2 white wing-bars. In first- extreme nw. South Carolina. Populations ins. Ontario fall males, streaking is present above but may be and central New York are increasing. limited to sides of back, the adult breast band is lack- Winter range. Winter range (Dunn and Garrett ing or restricted to the sides of the breast, and under- 1997, cf. Am. Ornithol. Union 1998) inmountains of n. parts have blurry streaking. The combination of a South America, on both east and west slopes of the bluish crown, pale supercilium, blurred ventral streak- Andes in Colombia, on east slopes in Venezuela, ing and wing-bars is fairly distinctive. In first-fall Ecuador, Peru, and n. Bolivia. Winter records exist females (the most greenish and yellowish plumage), also for the tablelands of e. Venezuela. Occasional the upperparts are unstreaked and the underparts are records on west slopes of Andes in Ecuador (J. Lyons only indistinctly streaked. First-fall individuals of both pers. comm.) and forested foothills as far as se. Brazil sexes are variably yellowish below, with females more (Dunn and Garrett 1997). extensively yellow than are males. First-spring (Alter- A few individuals recorded wintering in Grand nateIplumage)individualssimilartoadultsbutduller Cayman as nonbreeding residents (Raffaele et al. and not as boldly marked, with whitish supercilium 1998). Dee, Jan, and Feb specimen records are con- present in males (Dunn and Garrett 1997, Pyle 1997). fined to Venezuela, Colombia, Ecuador, and Peru Confusion with other species unlikely except for (D. Pashley pers. comm.). Sight records of individ- immature in its first fall, which is superficially similar uals in Pacific lowlands (C 500 m) of Costa Rica in to young female Blackburnian Warbler (D. fusca). Jan (D. Buehler pers. comm.). Young Blackburnian appears to have a dark triangular Other records. Casual west to N. Dakota and SW. auricular patch outlined by the lighter supercilium Manitoba, north to S.-central Ontario (North Bay), and pale side neck; Cerulean has only a light line over New Hampshire, Maine, Nova Scotia, and Newfound- the eye. Young Blackburnian may appear buffy below, land, and east to Bermuda, the Bahamas, and Greater Cerulean white with pale or more intense yellow. Antilles. Also casually recorded in w. North America Blackburnian in all plumages has pale streaking on in Colorado, New Mexico, Arizona, Nevada, n. Baja the sides of the back, Cerulean never does (Dunn and California, and California (where at least 13 records). Garrett 3997). Blackburnian also has longer tail. Of warblers with breeding ranges confined toe. North Immature Cerulean may also superficially resemble America, this species is among those least frequently immature Black-throated Gray Warbler (D. nigrescens) recorded in w. North America and, despite increasing but latter species is always gray above, never bluish intensity of searching, records seem to have become or greenish. less numerous since 1980. Roberson (1980) lists 9 California records prior to 1980; the number had TIMING OF MIGRATION increased only to 13 for the state in the mid-1990s A detailed summary of migration dates is presented (DUM and Garrett 1997). in Hamel 2000. Spring. Late Mar-mid-May, peaking in Apr along OUTSIDE THE AMERICAS Gulf Coast and early May in Midwest and Northeast Not recorded. (Hamel 2000). Florida records 23 Mar-21 May (Stevenson and HISTORICAL CHANGES Anderson 1994). In Louisiana (1988 study), first en- Conspicuous and abundant species throughout countered 13 Apr at Cameron Parish (F. Moore pers. the Ohio and Mississippi River valleys during nine- comm.). In Alabama, arrives late Mar in both coastal teenth century (Audubon 1856, Brewster 1875, Coues and mountain localities (Imhof 1976); migrants have 1878, Ridgway 1889, Widmann 1907); currently the left coastal situations by 21 Apr. Arrives Arkansas species no longer breeds in some areas of former very late Mar, becoming more numerous in third- abundance, such as much of the Mississippi Alluvial fourth week of Apr, widespread after that (James and Valley (Smith et al. 1996). While the overall geographic Neal 1986). limits of the breeding range have changed little during Typically arrives Tennessee mid-Apr (Robinson recent history, the relative abundance of the species 1990), with early dates of 29 Mar mid-state, 5 Apr in within the range has experienced considerable change west, and 11 Apr in east. In se. Missouri, arrives early (mostly declined) since the early 1900s (Hamel 2000). Apr, peak migration statewide in early May (Robbins Some of the increase in area of the range in the north- and Easterla 1991). Numbers increase to late Apr in east, e.g., in Quebec (Ouellet 1967) or Ontario (Eagles Illinois (Robinson 1996, Bohlen 1989), peak in Ken- 1987), may represent an extension of the limits of the tucky by 1 May (Mengel 1965). In Ohio, 25-30 Apr range, rather than a reoccupation of area from which arrival, few migrants detected after 20 May (Peterjohn the birds had been earlier extirpated. 1989). In Rhode Island, 55% of 58 records between 12-23 May (J. Ferren pers. comm.). Arrives s. Lower FOSSIL HISTORY Peninsula of Michigan first or second week of May, No information. less often late Apr, peaking about mid-May (R. J. Adams in Granlund et al. 1994). At Long Point Bird Observatory, Ontario, 27 of 28 records from 18 Apr to SYSTEMATICS 25 May (J. McCracken pers. comm.). Earliest arrival in Quebec, 1 May (Cyr and Larivee 1995). GEOGRAPHIC VARIATION; SUBSPECIES Few records; needs study. Latest Quebec No plumage variation documented; no subspecies departure 22 Aug (Cyr and Larivee 1995). In Michigan recognized. Genetic variation is currently under study (Wood 1951, Adams 1991), apparent departure as (Veit et al. 1998). early as late Jul, perhaps through Aug and into early Sep (R. J. Adams in Granlund et al. 1994). Rarely re- RELATED SPECIES ported in fall in New York, but recorded as late as 8 A hybrid Dendroica cqulea x Mniotilta varia Ott (Levine 1998). Four fall records for Rhode Island, (Cerulean x Black-and-white Warbler) was collected 17 Aug-16 Sep (J. Ferren pers. comm.). Aug-early Sep in 1954 (Parkes 1978). peak in Ohio, ending usually by 25 Sep, perhaps as late as 9 Ott (Petejohn 1989). Mid-Aug-early Sep de- parture from Missouri, with late dates 28 Sep 1897,26 MIGRATION Sep 1968 (Robbins and Easterla 1991). Coastal Alabama --w records 18 Jul-16 Sep, Coastal Plain records to 24 Sep NATURE OF MIGRATION IN THE SPECIES (Imhof 1976). Recorded inFlorida 11 Jul-15 Ott, where Medium- to long-distance complete migrant; no Taylor and Anderson (1973) noted TV tower kills resident populations. Migrates across Gulf of Mexico from late Aug to late Sep. Rare to sporadically common (Bonhote 1903, Bullis 1954, Crawford 1980)Migration late Aug-mid-Ott on Caribbeanlowlands and foothills occupies approximately 2 mo in spring, >4 mo in fall. of Costa Rica, usually to 500 m, sometimes to 1,500 m, Very southerly wintering areas give the species an with smaller numbers in central highlands and Pacific extended migratory route (Averill 1920, Banks and slope (Stiles and Skutch 1989). In Panama, late Aug- Baird 1978). Pattern of arrivals indicates that in- early Ott (Ridgely and Gwynne 1989). Very early ar- dividuals appear at known breeding locations 1 or rival on wintering grounds is demonstrated by 2 even 2 wk earlier than as transients at same latitude. records in Aug from Ecuador (Ridgely and Greenfield Fall migration begins very early, and individuals in press) and a Sep record from Peru (D. Pashley pers. may arrive on South American wintering grounds as comm.). Nevertheless, singing males recorded on early as Aug (DUM and Garrett 1997). breeding grounds as late as 21 Aug in Tennessee (C. Woodson pers. comm.) and 28 Aug in Michigan growth bottomland forests of the Mississippi Allu- (Brodkorb 1929). Latest North American record 2 vial Valley (Widmann 1895a, 1895b, 1897); these Dee in Newfoundland, but late fall records of this forests no longer exist. Mesic upland forests of species should be carefully evaluated because of the type this species used are now scarce as well possible confusion with Blackburnian Warbler (replaced by farmland); occurrence in flood plains (Lehman 1987). thus may be an artifact, rather than a preference. Records from western North America. Casual Expanding populations in ne. North America during migration in w. North America (see Distri- now occupy landscapes formerly cleared for agri- bution: other records, above), where more often culture (Oliamyk 1996). Thus, species will occupy recorded in fall (2 Sep-27 Ott; n = 13 records) than second-growth as well as mature forest. spring (17 May-6 Jun; n = 7 records). Most western Usually considered an area-sensitive species. records from California (n = 13; Dunn and Garrett Minimum forest-tract size varies, e.g. from 20-30 ha 1997). in Ohio to 700 ha in the Middle Atlantic states and 1,600 ha in Mississippi Alluvial Valley of Tennessee MIGRATION ROUTES (Robbins et al. 1989,1992, Petejohn and Rice 1991). Apparently from Andean wintering grounds to Mueller et al. (1999) suggest tracts >8,000 ha may be northern mountains of Colombia and Venezuela, required to support stable breeding populations in thence perhaps nonstop flight over Panama to Maya the Mississippi Alluvial Valley. Mtns. of Belize (Parker 1994), thence across Gulf In Ontario, however, found breeding in tracts as of Mexico to n. Gulf Coast of U.S. and northeast- small as 10 ha (J. Jones pers. comm.). Species response ward primarily through Mississippi and Ohio River to habitat fragmentation may reflect factors that valleys. Some may move north along coastal low- covary with fragment size, such as intensity of lands of Central America (Howell and Webb 1995). Brown-headed Cowbird (Molothrus ater) parasitism High concentrations noted at certain inland U.S. and of predation, rather than particular behavioral locations such as Kennesaw Mtn., GA (G. Beaton aversion to small fragment size or to edges (Robinson pers. comm.), and Sharps Ridge, TN (Robinson et al. 1995b, Hamel et al. 1998a). More research on 1990). Fall routes presumably the reverse of spring this topic is needed. (but few data), beginning in Jul and extending into No apparent preference for tree species or group Oct. Few data exist on concentrations in Central for nesting and foraging (Hamel 2000), although America in fall. Most records from w. North Amer- certain species or trees of certain crown classes may ica and from Bermuda and the West Indies have be used frequently in particular localities (Vanderah occurred during fall (Dunn and Garrett 1997). 1993 and pers. comm.; Oliamyk and Robertson 1996; and Hamel 2000 and unpubl.; contru Robbins MIGRATORY BEHAVIOR et al. 1992). Nocturnal migrant (Bonhote 1903, Bullis 1954, Minimum habitat requirements of this species Crawford 1980). Scant knowledge of stopover along the Roanoke River in N. Carolina: (1) a closed ecology is primarily from Parker (1994) in Belize, canopy; (2) presence of scattered, very tall, old- and G. Beaton (pers. comm.) in Georgia. Heavy fat growth canopy trees; (3) distinct zonation of canopy, loads in spring migrants that were killed by a tor- subcanopy, shrub, and ground-cover layers (Lynch nado on northern Gulf Coast suggest need for 1981). Floodplain areas of even-aged timber with extensive reserves for crossing Gulf of Mexico no old-growth trees contained few, if any, breeders (Wiedenfeld and Wiedenfeld 1995). in this region. In Tennessee study, Robbins et al. (1992) found Cerulean Warblers (1) to perch in CONTROL AND PHYSIOLOGY trees whose diameters were significantly larger No information. than average trees available to males in their ter- ritories, (2) to occupy territories containing trees with significantly larger diameters than average HABITAT for the stands in which the territories were located, and (3) to occur in stands dominated by trees with BREEDING RANGE larger diameters than the dominants of the average Routinely identified with predominantly forested stand in the study region. In e. Tennessee and w. landscapes, mature forest, large and tall trees of North Carolina, usually found in stands generally broad-leaved, deciduous species (Wilson 1811) with lacking in well-developed sapling or shrub layers an open understory; in wet bottomlands, or upland (D. Buehler pers. comm.). Oliamyk (1996: page i) situations including mesic slopes, and mountains, noted: “Within a territory, habitat surrounding from c30 to ~1,000 m elevation. Historical accounts successful nests was significantly more likely to described species as especially abundant in old- contain larger than average trees and a dense upper canopy, while unsuccessful nests were associated Quijos, Prov. Oriente, Ecuador, found considerable with a dense understory.” Hamel et al. (1994) variation in canopy structure at sites inhabited indicated that while Cerulean Warblers occur in by this species (W. P. Smith and PBH unpubl.). It areas dominated by large trees, within those areas remains to be determined whether architecture of the locations at which individuals spend their time forest canopies in wintering areas is similar to, or may not be predictable by tree diameters alone. differs from, that in breeding areas. Bent (1953), Harrison (1984), Oliamyk (1996), Generally occurs in mixed-species flocks of can- Oliarnyk and Robertson (1996), and others indicate opy-dwelling species, primarily tanagers. Winter that gaps in the canopy, or openings, are important habitat thus consists not only of geographical, for this species. In Missouri breeding habitats, elevational, and vegetational structure components! canopy cover averaged 85%, minimum value 65% but may include specific avifaunal components as (Kahl et al. 1985). This species persisted in stands well. Little information published on occurrence heavily damaged by Hurricane Opal on the Chatta- of Cerulean Warblers with mixed-species flocks of hoochee National Forest in Georgia (E. J. Williams tanagers (but see Robbins et al. 1992). The work of pers. comm.). On a Mississippi Alluvial Valley site Jones and Robertson (1997) in Venezuela has in- in Desha Co., AR, however, a severe ice storm was dicated that >90% of Cerulean Warblers associate followed by a decline in the population (Hamel et with mixed-species canopy flocks. Thus, this species al. 1998b). may be an obligate flock follower in the nonbreed- Important habitat elements for this species thus ing season, but this needs study. appear to be large tracts with big deciduous trees in mature to older-growth forest with horizontal heter- ogeneity of the canopy. The pattern of vertical dis- FOOD HABITS tribution of foliage in the canopy is also important. FEEDING SPRING AND FALL MIGRATION Main foods taken. Primarily insectivorous, for- Little information, particularly for South Amer- aging on insects in foliage. Also eats small amounts ica. Chapman (1917)collected2specimensat 1,370 m of plant material, as small fatty masses attached to on steep, heavily wooded slopes at the eastern edge fruits of some tropical trees, during migration (R. of the Colombian llanos. Greenberg pers. comm.). Fjeldsd and Krabbe (1990) found this species in Microhabitatforforaging. Takes food from leaf tropical and lower subtropical zones of the Andes, bases and foliage in canopy of a great variety of noting that during migration, individuals rarely trees (C. Woodson unpubl.). No tree species pre- occurred in the lower temperate zone. ferred. Foraging heights range from 2 to 3 to >45 m. Typically hops along twigs peering at upper and WINTER RANGE lower surfaces of leaves, petioles, and twigs. Male Limitedobservationsindicatethatwinteringbirds uses larger trees in more dominant canopy positions occupy canopy and borders of broad-leaved, ever- than does female, although the difficulty of observ- green forests and woodland at middle and lower ing silent birds in the dense canopy may complicate elevations (approximately 5OO-1,500 m) on the east determination of preference for particular tree sizes slopes of the Andes from Colombia to Peru and (C. Woodson pers. comm.). Females in Mississippi possibly Bolivia, as well as montane forests of Ven- Alluvial Valley sites forage in poison ivy (Toxico- ezuela (Salvin and Godman 1879-1904, Allen 1907, den&on radicans) vines extensively (PBH). Meyer de Schauensee 1966, Ridgely and Tudor 1989, Food capture and consumption. Primary mode Robbins et al. 1992, DeGraaf and Rappole 1995). of foraging is gleaning insects from leaves. Species Some (Terborgh 1989, Robbins et al. 1992, De- usually works from proximal portion of a twig Graaf and Rappole 1995) believe that this species is toward distal, peering intently on upper and per- confined to areas of old-growth native forest and haps more often lower surfaces of leaves for prey. that primary forest is thus a habitat requirement. Male often forages in portions of tree canopies with Others (P, Greenfield pers. comm., W. P. Smith and particularly dense foliage. Often standing on twig PBH unpubl.), however, have observed this warb- at the base of a leaf petiole, an individual will stretch ler in areas of second-growth or disturbed forests up, down, or out and pick a prey item from surface within the same elevational band in Ecuador. In of a leaf. Females in Mississippi Alluvial Valley Merida and Balinas states, Venezuela, Jones and often glean leaves and inflorescences of poison ivy Robertson (1997) associated the species withshade- (Toxicodendron rudicans) vines that encircle the boles coffee plantations and second-growth forest. Brief of canopy trees, working in a spiral around tree. To reconnaissance of habitats in which the species is a lesser extent, the species uses sallying and hover- routinely seen at the Cascada de San Rafael, on Rio gleaning to capture prey (PBH). DIET Major food items. Insects, especially homop- terans and larval lepidopterans, during breeding season (Howell 1924, Sample et al. 1993). No study of diet from winter or migration seasons. Quantitative analysis. Stomachs of 4birds taken in Alabama in 1912 contained: Hymenoptera (42% i -.----- .-..-.. -.i --..--_ ----L-I --.. -..--...-1. ..-. ..__ ._ _. ; of prey items); Lepidoptera (35%); and Coleoptera, including weevils (23%; Hamel 1992). Sample et al. (1993) reported on differences in diet of indi- viduals (n = 14) taken during studies of gypsy moth (Lymantriu dispar) invasion of W. Virginia forests. These birds had eaten Homoptera (52% of total bio- mass of gut contents); Lepidoptera, primarily lar- vae (37%); Coleoptera (7%); and small amounts of Hymenoptera, Diptera, Hemiptera, Araneae, and other arthropods. Study plots were treated with Diflubenzuron, an insecticide that interferes with molting of larval insects. Subsequent to treatment, 2 f------j +----&---+ Cerulean Warbler diets shifted from Lepidoptera / / I I toward Homoptera. Birds in control plots ate twice I I ___-- i-----..-. as much lepidopteran prey by weight as they did oc Ssclnds 0.5 :.c !.5 2.0 homopteran, while those in treatment plots ate 3 k!i7 times as much homopteran as lepidopteran prey. 6 ;.------.-- ,------The effect was most pronounced immediately after ;c / the treatment. Birds collected a month later all were eating more Iepidopteran than homopteran prey again; Lepidoptera/Homoptera ratio in treatment plots was 1.41, and that in control plots 4:l.

FOOD SELECTION AND STORAGE No information.

:.- ____ -.------..A----- .___ NUTRITION AND ENERGETICS 0.0 Cscor?ds Cl.5 1.0 i’; No information. Figure 2. Three song types of the Cerulean Warbler. From recordings made METABOLISM AND TEMPERATURE REGULATION by D. J. Borror in the collection of the Borror Laboratory of Bioacoustics No information. (BLB), The Ohio State University (A: BLB no. 14943, recorded in Vlnton Co., OH, 3 Jun 1978; 8: BLB no. 3349, recorded in Franklin Co., OH, 9 May 1958, DRINKING, PELLET-CASTING, AND DEFECATION C: BLB no. 10544, recorded in Pike Co., OH, 9 May 1970). Prepared by the No information. staff of BLB, using a Kay Elemetrics DSP 5900 Sona-Greph (with effective frequency resolution of 150 Hz and a 2OOpoint FFT transfono s&e). The songs appear to the author to correspond with those listed by Woodward (1997: 9-10) as follows: Fig. 2A “C”; Fig. 28 ‘IF”; and Fig. 2C “F”. mSOUNDS --- VOCALIZATIONS Woodward (1997) documented vocalizations and to Fig. 2A), ZEE ZEE ZEE ZIZIZIZI zeeet (similar to vocal behavior in Ontario, the same population Fig. 2B), or zz ZI ZI ZI zeeet (similar to Fig. 2C), where studied by Oliarnyk and Robertson (1996). capitalization indicates more heavily stressed syllables. Development. Not documented. Singing documented only in males. Woodward Vocal arruy. Songs of the Cerulean Warbler (1997) documented that the song type used by a male have been studied (Woodward 1997), calls have for his dawn song early in the season (“early” song, not. Songs typically involve 3 sections, an intro- serving a mate-attraction function) was replaced by a ductory set of longer figures, a middle section of different song type for dawn song later in the season shorter figures, perhaps on a slightly higher pitch, (“late” song, primarily used in intrasexual commun- and a final buzz. To the human ear, songs can be ication). Mid-morning song bouts early in the season described as ZHEE ZHEE ZlZlZIZl zzzeeet (similar were predominantly “early” song, while those later in the season alternated “early” and “late” songs. Songs song from their presumed mate (C. Woodson pers. of the species are not form encoded, in that individual comm., PBH). Countersinging by adjacent territory songs are typically used for mate attraction or for holders is common. Recognition of mates, neighbors, male-male interaction. Nor are they strictly perform- geographic variants, or other species has not been ance encoded, in which context can be used to deter- studied. Differences in responses to presumed mate mine the whether a song is an “early” or “late” song. attraction and territory defense singing in playback Phenology. Annual pattern of vocalizing has not experiments suggested to Woodward (1997) that the been studied. Sexual differences have not been docu- different song types in males’ repertoires serve these mented. separate functions. More work is needed on geographic Daily pattern. Singsduringmuchof daylighthours; and seasonal variation in vocalizations. for reasons not yet determined, individual male may or may not sing on any given day (PBH). NONVOCAL SOUNDS Places of vocalizing. Male sings from different Not documented. locations in canopy of trees in the breeding territory; may or may not use fixed song perches from day to day, although frequently sings from same individual BEHAVIOR tree (PBH). Appears to sing from higher perch after R having mated thanbefore (Woodward 1997). Vocalizes LOCOMOTION throughout the day. Male sings while foraging and Walking, hopping, climbing, etc. Generally hops while preening, occasionally sings in flight, as well as on small branches and twigs in the forest canopy, in while sitting on exposed perch (PBH). lateral or slightly upward direction. Female often Repertoire and delivery of songs. Geographic hops from vine to vine in poison ivy on tree boles in variation in songs studied by Woodward (1997) based both upward and downward direction. Walking and on samples of songs from se. Ontario (n = >33), sw. climbing not observed (PBH). Robbins et al. (1992) Ontario (n = ?), and s. Illinois (n = 28). Among 33 indicated that in a sample of all behaviors taken from males recorded in 1994, 8 different songs, combin- Tennessee, the Cerulean Warblers were found at an ations of syllables, recorded. Preliminary observa- average height of 17 m in a tree of average height of tions suggested that geographic variation in the 22 m. A much more extensive data set from Arkansas form of songs was small. Individual males usually and Tennessee bottomland hardwood forests indi- included 2, occasionally 3 (20% of males) songs in cated an average perching and foraging height of their repertoire. Males typically sang a single song- 15 m in a tree of average height of 22 m (PBH). type in repeat mode early in the season, presumably Flight. Short, direct flights between trees, occa- for mate attraction, and another song type later in the sionally accompanied by fluttering or slow flapping season. For birds with >2 song types, late-season song and spread tail that makes the white patches in the tail bouts included 2 song types presented alternately. and on the inner vanes of the primaries and second- Social context and presumedfunctions. Sings 2 dif- aries obvious to the observer below (PBH). Longer ferent songs, 1 mostly for mate attraction, apparently, flights also common. and the other primarily for territory defense. Similar Swimming and diving. Not known. pattern as in Vermivora, Parula, other Dendroica, Mnio- tilta, and Setophaga warblers (Spector 1992). The vocal SELF-MAINTENANCE repertoire is restricted structurally, however, compared No information. to these other species. Differences between intrasexual and intersexual communication are primarily in the AGONISTIC BEHAVIOR rate of delivery and pitch of the songs. Males sing at Physical interactions. Breeders can be very ag- slowerrate(7.1 songs/mindaytimef0.6SE, n -6)and gressive (PBH). Males sometimes attack each other at higher pitch (4.8 kHz rt 0.1 SE, n = 17) when the songs canopy heights of ~20 m, meeting in mid-air with are associated with attraction of potential mates, and audible collision. The birds grapple with each other at higher rate (8.6 f Or6 songs/min daytime, n = 6) and with bills and feet as they fall, spiraling to the ground lower pitch (4.3 It 0.1 kHz, n = 17) when the songs are with spread wings and tails. Similar fights observed associated with territory defense. Males may or may between females; when pairs interact aggressively at not respond to tape-recorded playback with singing territory boundaries early in the season, intrasexual behavior. Indeed, when attempts are made to catch fights between males and between females may be this species, lack of singing in response to playback is occurring at the same time (PBH). Female sometimes associated with higher probability of capture, sug- flies directly at and hits male, sometimes known to be gesting that higher levels of aggressiveness do not her mate, as male sits on a perch. Male occasionally involve vocalizing (PBH). Incubating females fre- does the same to female. quently call from the nest, apparently in response to a Communicative interactions. No information. SPACING not been distinguished from random distribution or Territoriality. Mean breeding territory size of habitat specificity. 1.04 ha f 0.16 SE based on 18 Ontario territories that Play. No information. ranged in size from 0.38 to 2.4 ha (Oliarnyk 1996). Nonpredatoy interspecific interactions. Murray Maximum breeding densities on published Breeding and Gill (1976) noted that Cerulean Warblers were Bird Censuses (Robbins et al. 1992) suggest that terri- attacked by both Blue-winged (Vermivoru pinus) and tories smaller than these are possible. Golden-winged warblers (V. chrysopteru). Fights Nature and extent of territory has not been studied between Cerulean Warbler females and female Amer- in detail. Although most observers treat the species as ican Redstarts, and between Cerulean Warblers and exhibiting all-purpose territories, this topic deserves Blue-gray Gnatcatchers observed in Mississippi Allu- further study. Observers have frequently noted that vial Valley study sites; individuals were contesting the species occurs in aggregates, groups, or “colonies” each other for nesting material, primarily spider webs during the breeding season. Bagg (1900) noted 25 (PBH). Aggressive interactions between Cerulean individuals inhabiting a single patch of woods in Warblers and American Redstarts, Least Flycatchers New York; Peck and James (1987) used this infor- (Empidonux minimus), Red-eyed Vireos (Vireo olivaceus), mation to infer that the species has a narrow habitat and White-breasted Nuthatches (Sittu curolinensis) preference. Statistical determination of the clumped common in Ontario (J. Barg pers. comm.). Interactions distribution of this species has not been made, how- between Cerulean Warblers and Red-eyed Vireos and ever. Study of this topic will help to interpret how Hooded Warblers (Wiisoniu china) observed in Arkan- these birds use their habitats, as well as how they sas (C. Kellner pers. con-m.), where the other species maintain their territories. displaced the Cerulean Warblers. Male apparently establishes and maintains territory primarily by singing, with some physical combat PREDATION involved (see Agonistic behavior, above). Kinds of predators. Little information. Blue Jays Interspecific territoriality hasnot beendetermined, (Cyunocittu cristutu) known to eat nestlings (J. Barg although frequent interspecific aggressive behavior pers. comm.). has been observed between this and a number of Manner of predation. No information. other species, including Blue-gray Gnatcatcher (Poliop- Response to predators. Few specific observations tila cuerulea), American Redstart (Setophuga ruticiilu), of responses to potential predators. Mobbing snakes, Northern Parula (Purulu americana), and other species giving alarm calls and “freezing” in response to (Hamel 2000). presence of Mississippi Kites (Ictiniu mississippien- Winter territoriality not documented. Observa- sis), suggest that the species recognizes these animals tions of Robbins et al. (1992) that mixed-species flocks as predators (PBH). contain at most a single individual (or pair, male and female; J. Jones pers. comm.) suggest need for addi- tional study. BREEDING Dominance hierarchies have not been observed. Individual distance. No information. PHEtiOLOGY Pairformation. Males usually arrive before females SEXUAL BEHAVIOR on the breeding grounds, often by at least a week. Pair Mating system and sex ratio. Apparently mono- formation commences soon after arrival of females. gamous (Verner and Willson 1969); not yet studied Nest-buiZding. Only by the female; may last from with marked birds. a few days to as much as a week or more. Pair bond. Duration of pair bond not demonstrated First/only brood per season. Generally raises a with marked individuals. Presumably, it exists for a single brood to independence. Few published egg single nesting attempt or perhaps breeding season. dates distinguish first from renestings. From 17 to 26 No published reports of polygamous matings. Court- Apr in n. Texas (Pulich 1988); late Apr-early Jul in ship displays, mate-guarding, and pre- and post- Mississippi Alluvial Valley of Arkansas and Tennes- copulatory displays have not been described. see, 50% of 25 nests initiated 9-21 May (PBH); late Extra-pair copulations. No information. May-early Jul in Michigan (Wood 1951); 4-17 Jun in Ohio (Peterjohn and Rice 1991); 24 May-27 Jun (n - 36 SOCIAL AND INTERSPECIFIC BEHAVIOR nests), 7-14 Jun (n -18) in Ontario (Peck and James Degree of sociality. Only speculation can be 1987); late May-early Jul in Ontario (Oliamyk 1996, J. brought to bear on this issue. Association between Jones and J. Barg pers. comm.). No data on duration wintering individuals and mixed-species flocks of of laying first to last eggs in clutch, on hatching dates, canopy-inhabiting species suggests interspecific or on when young depart from the nest. sociality to a degree. The often-noted tendency of this Secondllater brood per season. Can produce 2 species to occur in “clumps” in breeding season has broods in 1 season, but apparently does so rarely. in the Mississippi Alluvial Valley, color-marked pairs have renested after losing first nests (even with large young) to predators (PBH).

NEST SITE Selection Apparently both male and female help choose nesting location. Males and females observed together at locations where nests were later built; sometimes male went.to location before the female (G. Vanderah pers. comm., PBH). Nests in a great variety of tree species, at least 11 named and 3 genera listed in publications (Hamel 2000). Another 13 species identified among 70 nests in Mississippi Alluvial Valley (PBH). It is not clear if they actually select certain species in greater frequency than the species occur in the environment. Microhabitat. Nests usually placed on lateral limb of deciduous tree in mid-story or overstory canopy, usually concealed from above by clumps of live leaves on small twigs of the nest tree or by clumps of leaves or vines growing along the nest branch (Bent 1953, J, Jones pers. comm., PBH). - LaterPr&wic Molt w Prebasiil Nests often located over an open space (Bent 1953), w Preailemate which may be as small as 1 m between nest branch Breeding - Figure 3. Annual cycle of breeding, and a lower branch of the same tree. More often, migration, and molt of the Cerulean however, open space may be 5-20 m from nest to Migration Warbler across species’ range. Thick lines nearest vegetation below (PBH). Variety of situations show peak activity; thin lines, off-peak. in which nests are located within the canopy makes characterization difficult. Needs study; would benefit conservation of this bird. ished with gray shreds of bark, spider web, and some Site characteristics. Hamel (2000) summarized water-soaked pieces of newspaper. Cerulean Warbler published nest height information. Rangewide, based typically decorates outside of nest with some small upon 80 nests, mean nest height was 11.4 m f 0.41 SE, gray or white materials; different materials serve the range 4.6-18.3 m; mean distance from bole 3.38 m role in different parts of the range. f 0.37, range 0.9-7.3 m. Analysis of variance of nest Dimensions. From Bent (1953): Outside diameter height information indicates significant differences and height (n = 3 nests) based on 3 examples: 7 x 4% in mean nest height among localities. Hamel (2000) 5 cm. Inside diameter and depth (i.e., of nest cup), compared nest and vegetation heights from survey from the same nests: 3.4-4.5 x 2.2-2.5 cm. work in Ontario (Oliarnyk and Robertson 1996) and Microclimate. No information. the Mississippi Alluvial Valley (PBH) to these his- Maintenance or re-use of nests, alternate nests. torical data (rangewide values). All Mississippi Allu- From Oliarnyk and Robertson 1996, PBH. When re- vial Valley nest measurements were significantly nesting after nest failure, female routinely uses por- greater than values from Ontario and rangewide tions of old nest, probably caterpillar silk and spider values from the literature. Ontario values exceeded webs used to attach outer part of the nest to supporting rangewide values from literature for nest height, but branch, in the construction of new nest. Fresh lining not for distance from bole of tree. Differences among is apparently gathered for new nest. nest heights may relate to the general physiognomy Nonbreeding nests. Unknown. of the vegetation at the breeding locality (Hamel 2000). EGGS Shape. Ovate to short ovate (Bent 1953). NEST Size. Length and breadth of 50 eggs: 17 x 13 mm Construction process. Not described in detail. (Bent 1953). From collections of Western Foundation Constructed entirely by female (PBH). Length of time for Vertebrate Zoology (WFVZ), length: 16.68 mm to build nest varies from perhaps 3 to >8 d (PBH). (range 15.28-18.93); breadth: 12.78 mm (range 11.89- Structure and composition matter. Not yet char- 13.59); mass of empty shell: 0.076 g (range 0.062- acterized. Bent (1953) quotes Kirkwood concerning 0.091; n = 20 clutches, 77 eggs; L. Kiff and R. Corado materials in a single nest, which included brown bark pers. comm.). fiber, fine grass stems, a few black horse hairs; fin- Mass. No information. Color. “Grayish white, creamy white, or even very BROOD PARASITISM pale greenish white, and they are speckled, spotted or Identity of parasitic species. Robbins et al. (1992) blotched with ‘bay, ’ ‘chestnut,’ or ‘auburn,’ inter- list nest parasitism by the Brown-headed Cowbird mingled with spots of ‘light brownish drab,’ or (Molothrus ater) as an important factor in the decline ‘brownish drab.“’ (Bent 1953: 331). of the species. Study of nest parasitism by Brown- Surface texture. “Slight luster” (Bent 1953: 331). headed Cowbird is part of the protocol in studies in Eggshell thickness. No information. Ontario (Oliamyk 1996), Mississippi Alluvial Valley Clutch size. In Ontario, clutches at 6 nests ranged (PBH), Cumberland Plateau in Tennessee (D. Buehler from 2 to 5 eggs (mean 3.8 f 0.2 SE; Oliamyk 1996). In pers. comm.), and Illinois (S. Vanderah pers. comm.). 36 Ontario nests, range 1 to 4 eggs, mode 4 eggs (Peck No other nest parasites have been observed. and James 1987). Twenty clutches in WFVZ collections Frequency of occurrence, seasonal or geographic averaged 3.85 (R. Corado and L. Kiff pers. comm.). variation. Friedmann’s (1963, Friedmann et al. 1977) Additional data indicate that clutch size is typically records of parasitism by Brown-headed Cowbirds are 3 or 4 eggs (Hamel 2000); mean of 40 clutches in liter- taken from virtually throughout the range of the ature 3.78 eggs + 0.1 SE (range 2-5). Cerulean Warbler, suggesting that range overlap Egg-laying. No information. between the species has been of relatively long duration, and that the incidence of nest parasitism results from INCUBATION changes in habitat configuration brought about by Onset of broodiness and incubation in relation to human intervention rather than from changes in laying. No information. breeding ranges. Because Cerulean Warblers nest high Incubation patch. Only the female has a brood in the canopy of forests, where their nests are difficult patch (Pyle 1997, PBH). for humans to find, only detailed and intensive searches Incubation period. In Ontario, 11 (n = 5 nests) and for nests can be expected to provide even minimal 12 days (n = 3 nests; Oliarnyk 1996). estimates of actual rates of parasitism experienced by Parental behavior. Only female incubates (PBH). populations of Cerulean Warblers in different habitats. Male occasionally provisions his mate with food while Parasitism rates differ in different parts of the she incubates (Oliamyk and Robertson 1996, G. Van- breeding range. No parasitism by Brown-headed derah pers. comm.); no data on rate at which this Cowbirds observed by Oliamyk (1996) in Ontario. occurs. Incubation rhythm, duration of attentive per- In another Ontario data set, Peck and James (1987) iods not described. Several observers have noted a recorded 18% of 36 nests parasitized by Brown-headed characteristic behavior of female when leaving the Cowbirds. In the Cumberland Mtns. of Tennessee, 1 nest after an incubation or brooding bout: drops of 52 nests known to be parasitized (D. Buehler and vertically from side of nest with closed wings for sev- C. Nicholson pers. comm.). In the Midwest and the eral meters through space below nest, opening her Mississippi Alluvial Valley, where forest patches of wings only when well below the nest (called “bungee- all sizes are surrounded by a matrix of agricultural dropping”; G. Vanderah, J. Barg pers. comm.). lands, most potential breeding habitats for Cerulean Hardiness of eggs against temperaturestress; effect Warblers also support breeding Brown-headed Cow- of egg neglect. No information. birds, and parasitism of Cerulean Warbler nests has been observed in all study sites in the lower Mississippi HATCHING Alluvial Valley (PBH). Cowbirds observed parasitizing No information. Cerulean Warbler nests in continuous forest con- structed over flooded bottomlands at least 1.6 km from YOUNG BIRDS upland habitats and as high as 25 m above the ground No information; no studies of growth. (PBH). Of 66 nests found in the Mississippi Alluvial Valley 1992-1997, at least 9 were parasitized by Brown- PARENTAL CARE headed Cowbirds (Hamel 1998b). Brooding. Almost entirely by the female. No in- Timing of laying in relation to host’s laying. Un- formation on brooding rhythm. Roles and behavior known. One nest in Mississippi Alluvial Valley of parents not documented. produced a Cerulean Warbler fledgling and a Brown- Feeding. Both parents feed young. Initially male headed Cowbird fledgling a week apart (R. P. Ford provides most visits, later female increases her feedings unpubl.). as she devotes less time to brooding the young (G. Response to parasitic mother, eggs, or nestlings. Vanderah pers. comm., PBH). No published studies. No information. Nest sanitation. Both parents remove fecal sacs Effects of parasitism on host. No data. (PBH). Success of parasite with this host. No data. Study needed to ascertain whether cowbird parasitism is a COOPERATIVE BREEDING threat, whether it is exacerbated by forest fragmen- Not known in this species. tation, and how its impact varies across the range of the Cerulean Warbler; see Demography and popula- Number of broods normally reared per season. tions: reproductive success, below. Usually 1. Sufficient time is available in the southern part of the breeding range for a pair to raise 2 broods FLEDGLING STAGE successfully, but this has not been observed. Departure from nest. Little information. Nestling Proportion of total females that rear at least one period in Ontario between 10 (n = 6 nests) and 11 d (n brood to nest-leaving or independence. In Ontario, = 4 nests; Oliamyk 1996). At fledging, some tledg- 74% of pairs in 1 study produced young that fledged lings can fly weakly from the edge of the nest to an (Oliamyk 1996). adjacent tree (R. Ford and C. Woodson unpubl.). Growth. No information. LIFE SPAN AND SURVIVORSHIP Association with parents or other young. Audubon Total of 1,399 Cerulean Warblers (data through (1856) noted that adults often take their fledglings to Aug 1999; K. Klimkiewicz pers. comm.) have been areas with extensive tangles of grape vines (Vitis sp.). banded in 35 states (n = 1,245), 2 Canadian provinces Same behavior noted in the Mississippi Alluvial Valley (n = 129), and 6 countries on the migration and winter (PBH). Usually, where >l fledgling isproduced, adult grounds (n = 25). Majority of bandings in North male will attend some fledglings and the adult female America have taken place on breeding grounds, the rest (C. Woodson unpubl.). - May-Jul (n = 957); in s. U.S., majority of bandings Ability to get around, feed, and care for self. No occurred during spring migration, Mar-Apr. Only information. 1 individual has been banded during Dee, Jan, or Feb. Longevity record is 6-yr-old male (E. and J. IMMATURE STAGE Peartree pers. comm.). Another male was at least No information. 5 yr old when recaptured in 1998 (PBH). Only 1 of 1,399 (through 1999) banded birds has been recap- tured or recovered away from the banding locale DEMOGRAPHY AND POPULATIONS (Leberman and Clench 1975). No published studies of survivorship. MEASURES OF BREEDING ACTIVITY Age atfirst breeding; intervals between breeding. DISEASE AND BODY PARASITES Can breed successfully when 1 yr old (PBH); annually No information. thereafter. Clutch. Hamel (2000) summarized clutch sizes from CAUSES OF MORTALITY published sources, as well as Cornell Nest Record No information. Card Program and collections of WPVZ. Ontario: 3.8 eggs f 0.2 SE (range 2-5, n = 6 nests; Oliamyk 1996), RANGE mean 3.25, median 4 eggs (range 1-4, n = 36 nests; Peck Initial dispersalfrom natal site. No information. and James 1987); Pennsylvania: 3.82 eggs f 0.12 SE Fidelity to breeding site and winter home range. (range 3-4, n = 11 nests); Michigan: 4.33 eggs f 0.21 SE Individual color-banded birds have returned to breed- (range 4-5, n = 6 nests); New York: 3.58 eggs f 0.15 SE ing sites in Ontario (C. Oliamyk unpubl.) and in the (range 3-4, n = 12 nests). Number of clutches/breeding Mississippi Alluvial Valley (PBH) for at least 2 con- season usually 1; 2 or possibly even 3 may be laid if secutive years. Numbers of returning individuals earlier ones are lost (PBH). No published reports of are at present too small to estimate return rates. No renesting after successful fledging of first brood. reports of proportions of returning birds have been Annual reproductive success. For 27 nests found in made. No winter returns have been published. 1994 (n = 10) or 1995 (n = 17) on 3 study sites in On- Dispersal from breeding site or colony. Distances tario, 18 (67%) produced fledglings which, together moved by color-banded individuals (likely under- with observations of fledglings in territories where estimates average distances moved by individuals) no nests were found, represented 20 of 27 pairs generally

Ontario is likely to result in some management sug- from growing human populations limits the extent gestions. Some guidelines for land managers on effec- of such forest on the winter grounds. Cerulean Warb- tive silviculture of breeding habitat have been sug- lers have been found in other habitats (D. Buehler gested by Kahl et al. (1985), Hands et al. (1989), Hamel pers. comm.). Consequently, efforts to reforest now (1992), Robbins et al. (1992), and Flaspohler (1993). and in the future will likely be required to maintain Simple protection and silviculture of breeding nonbreeding habitats for Ceruleans. Encouragement habitats are the primary tools available to an individual of economically viable crops from primary or “altered” land manager. For Cerulean Warblers, silviculture of primary forest may offer a means to maintain forest breeding habitat means management for premium cover useful to this species. Such an approach has quality sawtimber products, involving long rotations been successful in maintaining habitats for other with intermediate treatments directed toward foster- species elsewhere in the tropics, e.g., where brazil ing long boles, large diameters, and full canopies of nuts, shade coffee, or other crops have been grown. dominant trees. It likely means strategies to produce Eflectiveness of measures. No published results a varied 3-dimensional stand with extensive devel- describe the response of Cerulean Warblers to pur- opment of vertical diversity, such as tall canopies of posefully conducted management activities. dominants and canopy emergents towering above midstory or intermediate trees. Conditions such as these can be produced by uneven-aged management APPEARANCE of extensive stands, and by old-growth or wilderness management techniques that foster an extensive net- In addition to distinct Juvenal, First Basic, First work of canopy gaps. Other strategies, including Alternate, and later, Definitive Basic and Alternate even-aged management with long rotations, may plumages (DUM and Garrett 1997), it is possible that also be effective. Second Basic and Second Alternate Plumages also Landscape context of the managed stands is an could be described. However, the necessary material important silvicultural consideration because the of known age does not currently exist. Distinct vari- species is area-sensitive, found only in the large tracts. ation in plumage with age cannot be distinguished as Future policy and land-use planning decisions that yet from individual variation in plumage. Color favor the existence of large tracts of forest, or land- terminology in the following is from Smithe (1975), scapes that are primarily forested, will aid these birds and molt and plumage descriptions follow Dunn and (Mueller et al. 1999). Where these landscapes can be Garrett (1997), Dwight (1900) and Pyle (1997), unless self-sustaining, i.e., maintained by their own produc- otherwise stated. tion, Cerulean Warblers will likely prosper. Where extensive economic subsidy is required to maintain MOLTS AND PLUMAGES the landscape in primarily forested condition, the Hat&Zings. Hatchlings have light mouse gray to future of the species would seem more tenuous. light drab natal down; bill, legs and feet pinkish buff Forest stand-management techniques that result (Oberholser and Kincaid 1974). in “ideal” or even “high quality” Cerulean Warbler Juvenalplumuge. Prejuvenalmolt complete,begins habitat cannot yet be stated. When developed and in the nest, completed shortly after fledgling. This tested, they will include parameters like length of plumage is described by Oberholser and Kincaid (1974: rotations, average height, diameter and density of 756), as “upper surface hair brown, very slightly canopy trees, tree-species composition, extent of washed with olive, broad median stripe on pileum ground and mid-story vegetative cover, minimum dull brownish; sides of head buffy white, long post- forest-tract size, and amount of canopy closure. Kahl ocular streak hair brown . . . lower surface dull buffy et al. (1985) have made specific proposals, applicable white.” in Missouri. Because of the variety of deciduous- Following description comes primarily from 2U.S. forest habitats occupied by Cerulean Warblers, it is National Museum specimens, no. 89243, Wabash, IL, premature to assume that the correlates of occurrence 20 May 1878, labeled male juvenile; and no. 82940, Mt. found by Kahl et al. (1985) in Missouri apply to the Cannel, IL, 27 Jul 1875, no sex or age listed on the habitats of this bird throughout its range or that these label. The latter specimen is molting from the Juvenal are the values that will provide habitat in which the to Basic I plumage. Juvenal plumage is a buffy gray species reproduces most successfully. Specific man- color corresponding to dark Drab or grayish horn ipulative research on habitats is necessary to make above. Below paler and whitish, the plumage has a such determinations with assurance. slight drab gray cast (no. 89243) or yellowish cast (no. WINTER-HABITAT MANAGEMENT. Little known; needs 89240). The gray color is darkest on the crown and study. Suggestions that only primary forest is ade- wings and tail. Each specimen has a median crown quate for this warbler (Robbins et al. 1992), if correct, stripe that extends from the bill to the nape, a pale mean that only protection of intact ecosystems will superciliary line, and 2 buffy wing-bars. Remiges are assure the future of the species. Intense pressure Sepia, Hair Brown, or Vandyke Brown. Inner margins of remiges are white as in older individuals. Leading coverts brown, edged greenish. Two white wing- edge of flight feathers, including alula, of 1 specimen bars. Rectrices Sepia or Dark Neutral Gray. Upperparts (no. 89243) appears variously as Pratt’s Payne’s uniformly Bunting Green, with no blue cast, and Gray or Light Sky Blue or as Citrine or Smoke Gray, without streaking. Crown and back are unstreaked, depending on light. Edge of flight feathers, including and usually’ the same color; when they contrast with alula, of the other specimen (no. 89240) appears Citrine each other, the crown is darker, almost Paris Green. or Smoke Gray, depending on the light. This plumage Underparts variably yellowish (Olive-Yellow, Sul- is replaced by Basic I plumage soon after the birds phur Yellow, Straw Yellow), or dull whitish washed leave the nest Pyle (1997) provides useful criteria for pale yellowish, especially on sides of throat, breast, aging and sexing the young birds. and flanks. Flanks diffusely streaked Grayish Olive. Basic I plumage. Prebasic I molt partial; includes Superciliary line yellowish. Postocular stripe grayish body-feathers, usually all median and greater wing- and ear-coverts pale grayish, washed yellow. Variable coverts, and often the greater alula, but no remiges or amount of white on inner webs of rectrices. rectrices (Pyle 1997). Prebasic I molt occurs very Alternate I plumage. Prealtemate I molt takes place shortly after the fledglings leave the nest and is com- on the winter grounds, probably during Feb and Mar, plete by JuI or Aug of their natal year. This plumage and includes most of the head and body plumage, but may be acquired before the fledglings become not the remiges. Pyle (1997) indicates that occasionally independent of their parents, which is earlier than 1 or 2 central rectrices are replaced in this and later Dwight (1900) believed. Unique characteristics of this Prealtemate molts. Virtually all the birds in a sample plumage are well described by Pyle (1997). of nearly 100 birds captured in the breeding season in MALE. Remiges Vandyke Brown edged grayish- Tennessee and Arkansas have fresh rectrices, indicating green, rectrices Dusky Brown with pale Sky Blue that these feathers were replaced during spring (PBH). cast to the leading edges. Alula and primary-coverts MALE . Sky Blue above with some black streaks on brownish with little to no blue edging. Upperparts the back and uppertail-coverts, and cancealed black greenish (Olive Yellow, Lime Green, or Parrot Green) patches on the sides of the crown. A white superciliary washed with blue or bluish (Pratt’s Payne’s Gray) line is present behind, and often reaching anterior to, with a greenish wash. One very bluish individual the eye. Auricular patch is Medium Plumbeous or (USNM no. 340979) had Sky Blue back feathers with Medium Neutral Gray. Underparts are white with a edges that appeared Lime Green, Bunting Green, narrow black or Blue Black band across the throat and Paris Green, or Apple Green. Usually the crown is black streaks along the sides of the breast and flanks. more greenish and the rump less so than the back. The Undertail-coverts extend beneath the tail virtually as rump may be Sky Blue. Some blackish streaking on far, in the closed tail, as the white patches in the 5 the back extending to the back of the crown. This is outer rectrices. Remiges Vandyke Brown and rectrices variable among individuals. Some individuals have Dusky Brown with greenish outer edges. Remiges only 1 or 2 streaked feathers, others are prominently contrast noticeably with the blacker tertials and streaked. Underparts white with variable amount of scapulars. Remiges have extensive white patches on yellowish cast (Olive-Yellow or Sulphur Yellow), more the inner webs. White, more or less squarish sub- pronounced in first than in later Basic plumages. terminal spots on inner webs of all but the central Breast band absent or restricted to sides of breast. rectrices; the latter may have white edges to inner Two white wing-bars. White patches in 5 outer rec- webs (Oberholser and Kincaid 1974). Spots decrease trices. Some blurry dusky streaks on the sides and in size from outer to inner rectrices and are smaller in flanks. Superciliary line whitish washed with Sulphur this plumage than in later ones (PBH). Primary-coverts Yellow. Usually more extensive and prominent behind contrast noticeably with the secondary-coverts; they the eye, the extent of this line is variable; in some are entirely dusky or, when a contrasting color is individuals, the portion anterior to the eye is much present on the leading edge, it is greenish. Greater more prominent than in others. The appearance of the and median wing-coverts tipped white, forming 2 leading edge of the remiges is also quite variable. All white wing-bars. edges in some individuals appear quite greenish FEMALE . Remiges Hair Brown or Vandyke Brown, (Citrine). In others the edges of the inner primaries are edged Citrine or greenish yellow, alula brown. Upper- greenish and those of the outer 2 or 3 primaries almost parts Bunting Green. Crown (appears Paris Green, Sky Blue. Others have base of the edges Sky Blue with Emerald Green, Cyan, Turquoise Green, or Peacock greenish tips. Others have primarily Sky Blue edges. Green depending on the light) contrasts with nape Edges of remiges of each bird further vary depending and back more than in Basic I plumage; however, upon the angle of the light in which they are examined. individual variation in this feature is great. Females FEMALE. The most greenish and yellowish plumage, in all plumages lack the black centers on the feathers with little if any bluish. Remiges Hair Brown or of the back and of the side of the crown possessed by Vandyke Brown, edged greenish yellow or Citrine, the males. Underparts whitish with variable amount alula brownish, sometimes with buff edging. Primary- of yellowish (Sulphur Yellow), with suffused streaks on flanks. Superciliary line white. Auriculars Olive- distinct black patches on the side of the crown thus Gray or Smoke Gray. Two white wing-bars. White almost creating a Cerulean Blue median crown stripe spots in rectrices as in male, but are smaller on each bordered by black and the black bordered by a Cerulean feather, and may occur only on outer 4 rectrices. Blue supercilium. Occasionally shows white feathering Overall similar to Definitive Alternate female except in postocular region. Back heavily streaked with black, often more yellowish below and more greenish above, and uppertail-coverts with broad black centers. Con- but considerable variation, with some appearing as siderable variation in brightness of blue on crown and bluish above as adults. Best distinguished from adults upperparts. Chin and throat white. Narrow Black or by duller, more worn flight feathers, and by primary- Blue Black band (width variable) across upper breast coverts without blue-green edges. often slightly veiled whitish. Remaining underparts Def3nitiveBasicpfuma. Definitive Prebasic molt white with bold deep blue-gray to blackish streaking complete, occurs after breeding during summer, (may be veiled whitish) on sides and flanks. Lesser presumably in Jr.6Aug, depending on the individual wing-coverts bluish; median and greater wing-coverts and its breeding success that season. blackish edged blue-gray on outer web and tipped MALE. Later Basic plumages of males are generally white, forming 2 wing-bars. Primary-coverts and re- similar to Alternate plumages in color and pattern. miges Sepia or blackish narrowly edged Sky Blue or Accurately aged individuals in older than Basic I Light Sky Blue on outer web, with tertials margined plumage have not been examined, so the complete blue-gray and edged white. Rectrices Blackish Neutral sequence of plumages cannot yet be described. Gray narrowly edged blue-gray with white subter- However, second and subsequent Basic plumages minal patches on inner webs of outer 5 pairs. appear to be more variable than second and subse- Males in later, probably Definitive Alternate, quent Alternate plumages. Males in second and sub- plumage differ from those in Alternate I plumage as sequent Basic plumages may or may not have exten- follows. The white superciliary line is typically not sive white superciliary lines, and the number of present, although a small number of white-tipped feathers on the back with black streaks is also variable. feathers may occur posterior to the eye. These are Usually, birds in Basic plumage have a narrower usually visible only in the hand. The auricular patch breast band than do those in subsequent Alternate is darker, blackish rather than Medium Plumbeous or plumages (band often partly veiled by white feather Medium Neutral Gray. The throat band is darker, tips). Nape is slightly grayer than the crown or the including black and Blue Black feathers, and may back, and the back is slightly grayer than the rump. In possibly be wider. Remiges and rectrices are blackish some fall specimens in older than Basic I plumage, and do not contrast noticeably with the scapulars. some of the blue feathers on the back are edged with These feathers are edged with Sky Blue or Light Sky pale greenish (Bunting Green, Lime Green, Paris Green Blue, not greenish as in the younger, second-year (SY) or Apple Green), reminiscent of the greenish backs of birds. Primary-coverts are blackish and may have the birds in their Basic I plumage. blue edges. In either case, they do not contrast with FEMALE. Remiges Hair Brown, rectrices Sepia, edged the secondary-coverts. with Sky Blue or Light Sky Blue. Alula Dusky Brown It isuncertain to what extent additional differences or Raw Umber with bluish edges. Upperparts green- between SY and after-second-year (ASY) individuals ish, unstreaked, with Cyan cast, especially on the exist, although the amount of white in the tail, as well rump. Crown and back contrast less than in corres- as the intensity of the blue in the upperparts, may ponding Alternate plumages, but this is very variable. increase with age. Underparts yellowish. Supercilium white. Two white F . Crown Cyan with slightly greenish (Paris wing-bars. White in tail probably more extensive Green) tinge. Remaining upperparts Parrot Green to than in Basic I, but this is variable. Overall similar to Cyan with slight greenish tinge and unstreaked. Definitive Alternate female except often more yellow- Super&urn (prominent behind eye) whitish or with ish below and more greenish above. slight Sulphur Yellow tinge. White arc under eye. Definitive Alternate plumage. Definitive Prealter- Lores and indistinct eye-line gray. Ear-coverts pale nate molt partial; occurs on the winter grounds Olive-Gray or Smoke Gray. Underparts dull whitish probably during Feb and Mar, and includes most of with variable Sulphur Yellow wash on sides of throat the head and body plumage, but not the remiges. See and upper breast. Blurred grayish or gray-green streak- Alternate I plumage. ing on sides and flanks. Remiges Dusky Brown to Raw MALE . Top of head (down to and including sub- Umber and primary-coverts similar, edged Sky Blue mustachial region) bluish, becoming bright Cerulean on outer web. Median and greater wing-coverts tipped Blueonforeheadandcrown, andSkyBlueonremaining white, forming 2 wing-bars. Rectrices Sepia, narrowly upperparts and rump; ear-coverts grayish, darker than edged Cyan on outer web and with white subterminal in Alternate I. Lores and eye-line slaty and sides of patches on inner webs of outer 4 or 5 pairs. crown (occasionally mid-crown) indistinctly and var- Crown contrasts with the back more strongly in iably streaked with black. Some old males have two Definitive Alternate female than in Alternate I. Upperparts have a more Cyan cast than in younger birds, but variation among individual females is very great. Upperparts in Alternate plumages are more bluish than in corresponding Basic plumages. Under- parts vary from white to yellowish white. Because underparts coloration appears to vary distinctly with ___.-___---.-.---.-.______light conditions, it is very difficult to age a female Cerulean accurately in the field. In the hand, age dif- 64.5 It 1.26 62.3 f 0.29 ferences parallel those of the male, primarily involving 42.4 f 0.25 40.9 f 0.27 9.62 f 0.13 9.56 f 0.10 the remiges and rectrices, which are browner and 3.62 f 0.03 3.57 f 0.06 more dusky in SY birds in Alternate I plumage than in 3.43 f 0.04 3.52 f 0.04 ASY birds, and possess more greenish edges in SY 15.7 f 0.14 14.8 f 0.20 birds and bluish white (Light Sky Blue) edges in older 11.5 It 0.38 11.1 individuals.

BARE PARTS needs be addressed first, grouped needed research Bill. Adult males: bill black with varying amounts activities on this species into 3 priority categories. of Plumbeous or Pratt’s Payne’s Gray on the lower High-priority activities. mandible; adult females: bill dusky with some brown (1) Determine winter survivorship, habitat dis- on the lower mandible (PBH). Fledglings: dull brown; tribution, and relative abundance by habitat in forests hatchlings: pinkish buff (Oberholser and Kincaid 1974). on the east slope of the Andes and elsewhere in north- Iris. Breeding adults: brown or reddish brown em South America. (PBH). Fledglings: dark brown; hatchlings: black ‘(2) Determine demography or population dynam- (Oberholser and Kincaid 1974). ics of the species in different parts of its range and Legs andfeet. Breeding adults: black, slaty, or dark under different silvicultural treatments of breeding horn, with soles of breeding males either buffy gray habitats. or pale Plumbeous or Pratt’s Payne’s Gray (PBH). (3) Identify landscape characteristics of Cerulean Fledglings: dull brown; hatchlings: pinkish buff Warbler occurrence, area-sensitivity, and distribution (Oberholser and Kincaid 1974). in relationship to forest fragmentation. (4) Identify preferred vegetation structure within habitats. MEASUREMENTS (5) Determine response of populations to land- management activities. LINEAR Moderate-priority activities. Linear measurements (see Table 1) are presented (6) Determine silvicultural activities that create good by Hamel (2000). Sexes differ (p Canada, Quebec Region, Mont&al. Harrison, H. H. 1984. Wood warblers’ world. Simon and Schuster, New Barker, S., and K. Rosenberg. 1997. Cerulean Warbler atlas project York. (CEWAP). Cornell Lab. of Omithol., Ithaca, NY. Howell, A. H. 1924. Birds of Alabama. Dep. Game Fish. of Alabama, Bent, A. C. 1953. Life histories of North American wood warblers. Pt. 1. Montgomery. U.S. Natl. Mus. Bull. 203. Howell, S. N. G., and S. Webb. 1995. A wide to the birds of Mexico and Bohlen,H.D.1989.ThebiidsofIlllnois.IndianaUnlv.Press,Bloomington. northern Central America. Oxford-Univ. Press, New York. Bonhote, J. L. 1903. Bird migration at some of the Bahama lighthouses. Imhof. T. A. 1976. Alabama birds. 2nd ed. Univ. of Alabama Press. Auk 20: 169-179. University. Brewster, W. 1875. Some observations on the birds of Ritchie County, Jackson, J. A., ed. 1981. The “Mid-South bird notes” of Ben B. Coffey, Jr. West Virginia. Ann. Lye. Nat. Hist. New York 11: 129-146. Spec. Publ. no. 1, Mississippi Orrdthol. Sot., Mississippi State. Brodkorb, P. 1929. Notes from Berrlen County, Michigan. Auk 46: 397- James, D. A., and J. C. Neal. 19%. Arkansas birds: their di&bution and 398. abundance. Univ. of Arkansas Press, Fayetteville. Bullis, H. R., Jr. 1954. Trans-Gulf migration, spring 1952. Auk 71: 298- James, F. C., C. E. McCulloch, and D. A. Wiedenfeld. 1996. New 305. approaches to the analysis of population trends in land birds. Chapman, F. M. 1917. The distribution of birdlife in Colombia: a Ecology 77: 13-27. contribution to a biological survey of South America. Bull. Am. Jones, J,, and R. J, Robertson. 1997. Abstract 75: Winter ecology of the Mus. Nat. Hilt. 36: l-729. Cerulean Warbler in modified Venezuelan landscapes. Presented Coues. E. 1878. Birds of the Colorado vallev. U.S. Geol. Surv. Terrlt. to the 115th stated meeting of the Am. Omlthol. Union, 13-16 Aug Misc. Publ. 11. 1997. MlnneapoIis-St. Paul, MN. Crawford, R. L. 1980. Wind direction and the species composition of Jones, J., and R. J. Robertson. 1998. Cerulean Warblers ln Venezuela: autumn TV tower kills in northwest Florida. Auk 97: 892-895. winter ecology and habitat use patterns. N. Am. Omithol. Con- Cyr, A., and J. Larlv&. 1995. Atlas saisonnler des oiseaux du Qubbec. ference, St. Louis, MO, 6-12 Apr 1998. Sod& de Loisir omlthologlque de l’Estrie, Univ. of Sherbrooke Kahl, R. B., T. S. Baskett, J. A. Ellis, and J. N. Burroughs. 1985. Char- Press, Sherbrooke, Qu&ec. acteristics of summer habitats of selected nongame birds ln Mis- Eagles, P. F. J. 1987. Atlas of the breeding birds of Ontario (M. D. souri. Univ. Missouri-Columbia Agrlc. Exp. Stn. Res. Bull. 1056. Cadman, P. F. J. Eagles, and F. M. Helleiner, eds.). Univ. of Waterloo Leberman, R. C., and M. H. Clench. 1975. Bird-banding at Powdermill, Press, Waterloo, ON. 1974. Powdermill Nat. Reserve, Res. Rep. no. 35. DeGraaf, R. M., and J. H. Rappole. 1995. Neotropical migratory birds: Lehman, P. 1987. Immature Blackbumian and Cerulean warblers: a natural history, distribution, and population change. Comstock cautionary note. Birding 19: 22-23. Publ. Assoc., Ithaca, NY. Levine, E., ed. 1998. Bull’s birds of New York State. Cornell Univ. Press, Dunn, J. L., and K. L. Garrett. 1997. A field guide to warblers of North Ithaca, NY. America. Houghton-Mifflin Co., Boston, MA. Lynch, J. M. 1981. Status of the Cerulean Warbler in the Roanoke River Dwight, J., Jr. 1900. The sequence of plumages and moults of the basin of North Carolina. Chat 45: 29-35. passerine birds of New York. Ann. N.Y. Acad. Scl. 13: 73-360. Maurer, B. A. 1994. Geographical population analysis: tools for the Fjelds&, J., and N. Krabbe. 1990. Birds of the high Andes. Zool. Mus., analysis of biodiversity. Blackwell Scientific Publ., Oxford. Univ. of Copenhagen and Apollo Books, Svendborg, Denmark. Mengel, R. M. 1965. The birds of Kentucky. Am. Omithol. Union, Flaspohler, D. 1993. Wisconsin Cerulean Warbler recovery plan. Ornlthol. Monogr. 3. -8. .a I I.

Meyer de Schauensee, R. 1966. The species of birds of South America Robinson, S. K., S. I. Rothstein, M. C. Brittlngham, L. J. Petit, and J. A. and their distribution. Acad. of Nat. Sci. of Phlla., Philadelphia, PA. Grzybowski. 1995a. Chapter 15. Ecology and behavior of cowbirds Mllne, 8. T. 1991. Chapter 9. Lessons from applying fractal models to and their impact on host populations. Pp. 428-460 in Ecology and landscape patterns. Pp. 199-235 in Quantitative methods in managementofNeotropica1mlgratorybirdsfT.E.MartinandD.M. landscape ecology (M. G. Turner and R. H. Gardner, eds.l.Springer- Finch, eds.1. Oxford Univ. Press, New York. Verlag, New York. Robiion,S. K., J. Terborgh,and J. W. Fitzpatrick. 1988. Habitat selection Moore, F. R., and T. R. Simon. 1992. Habitat suitability and stopover and relative abundance of migrants ln southeastern Peru. Pp. 2296 ecology of Neotropical landbird migrants. Pp. 345-355 in Ecology 2387 in Acta XIX Congres. Int. Ornithol. (H. Ouellet, ed.). Univ. of and conservation of Neotropical migrant landblrds fJ. M. Hagan, Ottawa Press, Ottawa, ON. III and D. W. Johnston, eds.). Smithson. Inst. Press, Washington, Robiin, S. K., F. R. Thompson III, T. M. Donovan, D. R. Whitehead, -._.D.C. and J.Faaborg.1995b.Reglonalforestfragmentationand thenesting Moseley, E. L. 1947. Variations in the bird population of the north- success of migratory birds. Science 267: 1987-1990. central states due to climatic and other changes. Auk 64: 15-35. Robinson, W. D. 1996. Southern Illlnols buds. Southern Illinois Univ. Mueller, A. J., C. R. Loesch, and D. J. Twedt. 1999. Development of Press, Carbondale and Edwardsville. management objectives for breeding bids in the Mississippi Alluv- Salvin, O., and F. D. Godman. 1879-1904. Biol. Cent.-Am. Aves. Vol. 1. ial Valley. Proc. Partners in Flight International Workshop, Cape Sample, 8. E., R. J. Cooper, and R. C. Whlhnore. 1993. Dietary shifts May, NJ, l-5 Ott 1995. among songbirds from a diflubenzuron-treated forest. Condor 95: Murray, 8. G., Jr., and F. B. Gill. 1976. Behavioral interactions of Blue- 616-624. winged and Golden-winged warblers. Wilson Bull. 88: 231-254. Sauer, J. R. 1993. Monitoring goals and programs of the U.S. Fish and Nicholson, C. P., and D. A. Buehler. 1998. Nesting ecology of the Wildlife Service. Pp. 245-251 in Status and management of Cerulean Warbler in the Cumberland Mountains of Tennessee. N. neotropical migratory birds; 21-25 Sep 1992; Estes Park, CO (D. M. Am. Omithol. Conference, St. Louis, MO, 6-12 Apr 1998. Fmchand P. W. Stange1,eds.I. U.S. Dep. Agric., For. Serv. Gen. Tech. Oberholser, H. C., E. B. Kincaid, Jr. 1974. The bird lie of Texas. Vol. 2. Rep. RM-229, Fort Collins, CO. Univ. of Texas Press, Austin. Smith, W. P., P. B. Hamel, and R. P. Ford. 1996. Mississippi Alluvial Oliamyk, C. J. 1996. 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Part 1: among populations of Cerulean Warbler Dmdroicn cerulea using Columbidae to Ploceidae. Slate Creek Press, Bolinas, CA. molecular methods. Abstract of poster, 22nd Int. Ornlthol. Congr., Raffaele, H., J. Wiley,O. Garrido, A.Keith, and J. Raffaele. 1998. Aguide Durban, South Africa, 16-22 Aug 1998. Ostrich 69: 357. to thebiids of the West Indies. Princeton Univ. Press, Princeton, NJ. Vemer, J., and M. F. Wlllson. 1969. Mating systems, sexual dimorphism, Ridgely, R. S., and P. J. Greenfield. In press. The birds of Ecuador. Vol. and the role of male North American passetine birds ln the nesting I: status, distribution and taxonomy. Cornell Univ. Press, Ithaca, cycle. Am. Ornithol. Union Monogr. 9. NY. Villard, M.-A., and 8. A. Maurer. 1996. Geostatlstlcs as a tool for Ridgely, R. S.,and J. A. Gwynne, Jr. 1989. A guide to the birds of Panama, examining hypothesized declines ln migratory songbirds. Ecology wlthCostaRlca,Nicaragua,andHonduras.2nded.PrincetonIJnlv. 77: 59-a. 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A warbler in migrants by tornado and storm in Louisiana, April, 1993. J. Field trouble: D&droica &ulea. Pp. 549562 in Ecology and conservation Ornlthol. 66: 70-80. of Neotropical migrant landbllds fJ. M. Hagan, III, and D. W. Wilson, A. 1811. American ornithology. Vol. 3. Bradford and Inskeep, Johnston, eds.). Smithson. Inst. Press, Washington, DC. Philadelphia, PA. Robbms, M. B., and D. A. Easterla. 1991. Bids of Missouri: their Wood, N. A. 1951. The birds of Michigan. Univ. Mlch. Mus. Zool. Misc. distribution and abundance. Univ. of Missouri Press, Columbll. Publ. no. 75. Roberson, D. 1980. Rare birds of the west coast of North America. Woodward,R.L.1997.Characterizationandslgniflcanceofsongvariatlon Woodstock Publ., PacificGrove, CA. inthecerulean Warbler(Dendroicecemles).Master’sthesis,Queen’s Robinson, J. C. 1990. An annotated checklist of the birds of Tennessee. Univ., Kingston, ON Univ. of Tennessee Press, Knoxville. 20 CERULEAN WARBLER

Frank Gill, President The Birds of North America Frederick Sheldon, Treasurer Patricia Warner, Secretary The Birds of North America ‘series provides comprehensive, authoritative summaries of current knowledge of the breeding bird CTORS species of North America. Each of these accounts includes a major Kemp Battle bibliography of references as well as unpublished information. Their Erica Dunn purpose is to enable informed conservation management of our native John Fitzpatrick birds and to define directions for future research. Accounts are Edward W. Rose published separately to ensure timely availability of their contents. Frederick Sheldon Dennis Waters The Birds of North America accounts (ISSN 10616466) are published Glen Woolfenden by The Birds of North America, Inc., with support from the American Ornithologists Union, Cornell Laboratory of Ornithology, and the Academy ofNatural Sciences. Published by The Birds of Nor&.Amer- Alan Poole, Editor ica, Inc. Printed by Smith-Edwards-Dunlap Company, Philadelphia, Frank Gill, Editor Patricia Warner, Managing Director PA. All rights reserved. Christine Bush, Managing Editor Keith Russell, Assistant Editor The Birds of North America is supported by charitable and govem- Louis Bevier, Assistant Editor mental organizations including: The Office of Migratory Bird Sandra Sherman, Assistant Editor Management (USFWS), National Fish and Wildlife Foundation, The Anne-Marie Hinds, Editorial Assistant McLeanContributionship, The Geraldine R. Dodge Foundation, The Richardson Foundation, and the American Birding Association. ASSOCIATE EDITORS Benefactors of this program include Wallace C. Dayton and Joseph Sheila Conant and Helen Taylor. William Dawson Sandra Gaunt Kenn Kaufman Don Kroodsma SUBSCRIPTIONS Marie Morin To subscribe or request more information write: The Birds of North America 1900 Benjamin Franklin Parkway Kermit Hummel Philadelphia, PA19103-1195 Henry Reath http: / / www.birdsofna.org Kathy Reid Nancy Steele

ABOUT THE AUTHOR Paul B. Hamel received a Ph.D. from Clemson University in 1981. He is currently Research Wildlife Biologist at the Southern Hardwoods Laboratory of the USDA Forest Service, Southern Forest Experiment Station, Stoneville, MS. His interest in Cerulean Warbler began with the opportunity to study the birds in the Warner Parks in Nashville, TN, in 1984. It intensified when BBS results indicated that the birds were declining rangewide and that threats to their persistence existed throughout the annual cycle. His current studies of the species reflect his primary research interest in ecology of birds of bottomland hardwood forests. Current address: USDA Forest Service, Center for Bottomland Hardwoods Research, P.O. Box 227, Stoneville, MS 38776, USA. E-mail:[email protected].

RECOMMENDED CITATION Hamel, P. B. 2000. Cerulean Warbler (Dendroica cerulea). In The Birds of North America, No. 511 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.