SPECIES

Bald Eagle Haliaeetus leucocephalus Scientific name definitions

David A. Buehler
Version: 2.0 — Published October 7, 2022

Sounds and Vocal Behavior

Introduction

Though among the most iconic bird species in North America, the vocalizations of the Bald Eagle are less well known and often not recognized by the public. The sound most often attributed to the species in movies is the scream of Red-tailed Hawk (Buteo jamaicensis), rather than the weak, gull-like calls typically given by the Bald Eagle. Its call was described by Brewster (232) as “weak in volume and trivial in expression…it consists of seven or eight notes given rather quickly, but haltingly and with apparent difficulty, as if their author was choking or gasping for breath. It cannot fittingly be called a scream, but is rather a snickering laugh expressive of imbecile derision, rather than anything else. My notes render it thus— Ki-ki-ki-ki-ki-ki-ker.” It was characterized by Bent (8: 331) as “ridiculously weak and insignificant.” The functions of vocalizations are largely unknown and need study (18).

Vocalizations

Development

After hatching, calls start out as a distinctive, single-note tonal peep (233), with little range in frequency. Sounds develop in volume and complexity, so that by day 30, the call has some of the basic characteristics of adult vocalizations. There is no direct evidence of vocal learning. At fledging, the Cheeping Call is given persistently is associated with begging for food. Cheeping is also used as an alarm call and to communicate with adults (234). Scream calls are evident at about 4 weeks after fledging (234).

Vocal Array

Three distinctive calls were described with sonograms by Verner and Lehman (235), and three also described by Pieplow (236), the terminology from which is followed here. Other rarely heard vocalizations likely exist but are not well described or studied.

Keek. Also known as the Chatter Call (Figure 3A), this is the most commonly heard vocalization. It typically consists of 3 or 4 introductory notes separated by short gaps of silence (< 1 s) followed by a rapid sequence of descending, piping notes, usually 6–9 notes in call sequence: "kwit kwit kwit kwit kee-kee-kee-kee-ker." The whole vocalization is relatively high-pitched (ca. 3–5 kHz), and reminiscent of some sounds made by certain gulls (Laridae)

Scream. Also known as the Peal Call: a high-pitched, prolonged, gull-like cry, often repeated 3–5 times. Individual notes are long (ca. 0.5 s), slightly rising, and often have a short higher-pitched voice break at the end. Significant variation, with some versions grading into Keek series. Reported to give a higher-pitched version of the Scream in response to threats near its nest (see Social Context and Presumed Functions of Vocalizations, below.)

Bark. Much less commonly heard than Keeks or Screams, the Bark is a lower-pitched, short, nasal quiet note. Usually give in a series of ca. 5–7 notes/s. Most often heard by birds near nests, and may be indicative of alarm.

Copulation call. Females will give a soft, high-pitched note, repeated several times, that is distinct from the other call types and apparently associated with copulation (237). Keek series also given during copulation by both individuals.

Individual Variation

Discriminant function analysis of sonograms successfully identified 83–100% of individuals (238). Within-breeding season variability in call characteristics occurred for most (14 of 16) breeding adults studied in Arizona (238). Year-to-year variability in sonogram characteristics made the technique problematic for the identification of individuals in the wild (238).

Geographic Variation

None known, but poorly studied.

Phenology

All calls are reportedly given all year (236).

Daily Pattern of Vocalizing

Will vocalize at almost any time, but is mostly quiet at night.

Places of Vocalizing

The Keek Call is often given when an adult approaches its nest. Vocalizations are common in communal roosts when new individuals enter the roost or change perches. Vocalizations are very common at feeding sites, most often as part of agonistic interactions.

Sex Differences

Poorly known. Females reported to give a unique call during copulation. Other vocalizations appear to be given by both sexes.

Social Context and Presumed Functions of Vocalizations

Verner and Lehman (235) studied Bald Eagle calls given in response to threat from humans approaching nests. The most common vocalization given was the Keek Call with the Scream Call also commonly given in response to human approach. Territorial adult emits a high-pitched Scream Call as a threat vocalization, when other birds or humans approach nest site (18). Individuals also give Scream Call to fend off attack at communal feeding sites (200). Also reported to emit a short, staccato Hic Call (likely referring to the Bark Call) while circling over its nest (239). Male and female often vocalize during nest incubation exchanges; the incubating bird calls first, and after several vocal exchanges, the pair switches positions (240). The soft, high-pitched note given by female apparently signals the male that she is ready for copulation (237).

Nonvocal Sounds

None reported.

Recommended Citation

Buehler, D. A. (2022). Bald Eagle (Haliaeetus leucocephalus), version 2.0. In Birds of the World (P. G. Rodewald and S. G. Mlodinow, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.baleag.02