The Status and Occurrence of Little Blue Heron (Egretta caerulea) in British Columbia. By Rick Toochin and Don Cecile. Revised: June 20, 2023.

The Little Blue Heron (Egretta caerulea) is a small elegant species of heron that is found breeding along the Atlantic Coast of North America from southern Maine south to Florida, as far west as central Oklahoma, south east Kansas, Arkansas, north western Tennessee, western Kentucky, and southern Illinois. In North America, there is extensive post-breeding dispersal towards north and west of the breeding range (Rodgers and Smith 2012). This is especially true of juvenile birds, with birds reaching southeastern Saskatchewan across southern Canada to the southern Maritimes (Godfrey 1986, Rodgers and Smith 2012). There are a few records for Newfoundland, occasionally Greenland, and three records for the Azores (Dunn and Alderfer 2011, Rodebrand 2012, Rodgers and Smith 2012). The population of United States is migratory, with birds from the eastern areas of their range moving south through Florida towards Cuba (Rodgers and Smith 2012). The Little Blue Herons found in the more western part of their range head towards Gulf of Mexico and Yucatan Peninsula in southeastern Mexico (Rodgers and Smith 2012). Wintering Little Blue Herons can occur from the southern United States to northern parts of South America (Rodgers and Smith 2012). In Caribbean, many birds are sedentary (Rodgers and Smith 2012). The Little Blue Heron is a rare migrant to Paraguay, and is accidental south into Argentina (Rodgers and Smith 2012). This species inhabits mangroves, coastal mudflats, wetlands, rivers and lakes. It is somewhat more common in coastal environments (Rodgers and Smith 2012). The Little Blue Heron is a resident in southern California with a small, localized breeding population and, as a result, is not a review species in that state by the California Bird Records Committee (Hamilton et al. 2007). There are accepted records for Oregon by the Oregon Bird Records Committee (OFO 2012). In Washington there are three accepted records by the Washington Bird Records Committee (Wahl et al. 2005, WBRC 2012). There are no records for the State of Alaska (West 2008). In British Columbia the Little Blue Heron is an accidental species and is very rarely ever reported (Toochin et al. 2013, Please see Table 1).

 

The Little Blue Heron is unique amongst North American herons as it is the only species with two distinct colour morphs for mature and immature birds (Sibley 2000, Rodgers and Smith 2012).  The Little Blue Heron is a small, dark bird that averages 61 cm in length and is similar in size to the Tricolored Heron (Egretta tricolor) which is 66 cm and the Snowy Egret (Egretta thula) which is 61 cm (Dunn and Alderfer 2011). The adult males and females look similar, but the young look completely different to the adults (Sibley 2000). Adult birds have a purple-maroon head and neck (Dunn and Alderfer 2011). The rest of the plumage is slate gray (Dunn and Alderfer 2011). The long neck is usually held in an "S" shaped curve while the bird is at rest or in flight (Rodgers and Smith 2012). This adult plumage once acquired is held year round (Sibley 2000, Dunn and Alderfer 2011). During the breeding season the adult Little Blue Herons develop head and neck plumes (Rodgers and Smith 2012). The heron's long, slender bill curves slightly downward, and is also dark gray but has a black tip (Dunn and Alderfer 2011). The eyes are yellow and the legs and feet are dark (Sibley 2000). The immature birds are unique to North American herons because they have all white body plumage (Rodgers and Smith 2012). This plumage is held between the months of June until the early spring of the next year (Sibley 2000). They have a blue bill, greenish lores with a black tip and dull green legs (Sibley 2000, Dun and Alderfer 2011). The wings have dusky markings on the tips of the primary feathers (Sibley 2000, Dunn and Alderfer 2011). This is noticeable both in flight and on sitting birds and can vary in intensity amongst individual birds (Rodgers and Smith 2012). The immatures stay white through their first summer, fall, and into winter, but start molting in February into the dark color of an adult, and often look this way until June (Sibley 2000, Rodgers and Smith 2012). In their second year, they develop a “calico” look where they will have a mixture of purple-blue feathers and white feathers all over the body as they mature into adult plumage (Sibley 2000, Dunn and Alderfer 2011, Rodgers and Smith 2012).

 

As immature birds, the Little Blue Heron’s unique all white plumage makes this species look similar to all of North America’s commonly occurring Egrets. The species that it most looks like is the Snowy Egret (Sibley 2000). The Snowy Egret holds its immature plumage from July to April the following spring (Sibley 2000). The Little Blue Heron is slightly smaller than the Snowy Egret in wingspan and weight, but is about the same height (Sibley 2000, Dunn and Alderfer 2011). Adult birds are easily identified from immature Little Blue Herons (Dunn and Alderfer 2011). The immature plumage of Snowy Egret has bright green legs with some black on the forelegs (Sibley 2000). The primaries lack any dark markings and are pure white (Sibley 2000). The lores are normally yellow, but some birds can show a greenish color similar to immature Little Blue Heron (Sibley 2000, Dunn and Alderfer 2011). The bill of the immature Snowy Egret is straighter, less curved and darker along the entire upper mandible than the immature Little Blue Heron (Sibley 2000). The Snowy Egret does use the same type of environments to feed as the Little Blue Heron so careful attention to detail should be given by observers to any out of range immature birds due to their similarities (Sibley 2000, Dunn and Alderfer 2011).

 

The Great Egret (Ardea alba) is another species that is superficially similar to an immature Little Blue Heron. In all ages the Great Egret is a much larger bird in overall size and has black legs and feet with a bright yellow bill (Sibley 2000, Dunn and Alderfer 2011). They are found in similar habitats, but should be easily distinguished by observers as they are smaller and have different plumage and structural characteristics (Sibley 2000, Dunn and Alderfer 2011).

Another species that is all white is the Cattle Egret (Bubulcus ibis) which shouldn’t pose any identification problems for observers. The Cattle Egret is a quite a bit smaller than the Little Blue Heron (Dunn and Alderfer 2011). The immature birds hold their plumage from July to October and have a small dark bill with short dark legs (Sibley 2000). Adult birds hold their winter plumage from the months of August to February the next year (Sibley 2000). They have a short yellow bill but with short dark legs (Dunn and Alderfer 2011). The adult breeding plumaged Cattle Egrets will hold this plumage from March to July and develop orange-reddish legs, orange chest plumes, orang back plumes and orange head plume (Sibley 2000). This species in all ages should be easily recognized by observers, and poses no reason to be confused with an immature Little Blue Heron. The Cattle Egret is most often in found in the presence of livestock, and will even take to riding the backs of such animals. This is behavior never exhibited by the Little Blue Heron (Sibley 2000, Dunn and Alderfer 2011).

 

The other species that can look superficially like a Little Blue Heron is the white morph of the Reddish Egret (Egretta rufescens). To date there are no British Columbia records of Reddish Egret, but it is important to know the differences. The Reddish Egret is a very large, tall bird (Sibley 2000). In all plumages the Reddish Egret has black legs (Sibley 2000). All white morph birds have a white head, white neck with long white neck plumes, a white body, white wings and a white tail (Sibley 2000, Dunn and Alderfer 2011). The immature birds have dark lores and a long dark bill that gradually becomes pinker (Sibley 2000). Adult white morph birds in breeding plumage have a pink base to the bill with a black tip (Sibley 2000). In winter plumage, the bill is mostly dark with a light area in the middle of the bill where the mandibles meet (Sibley 2000). The Reddish Egret is usually found singly, in expanses of shallow salt water, where they are very active and like to chase fish on foot by running, jumping and spinning (Sibley 2000, Dunn and Alderfer 2011). This type of behavior is never exhibited by the Little Blue Heron (Sibley 2000). 

 

The Little Blue Heron is an accidental species in British Columbia with only four Provincial records (Toochin et al. 2013, Please see Table 1). All the Provincial records have been immatures birds that have turned up in the fall (Toochin et al. 2013, Please see Table 1). This fits perfectly with the species pattern of post-breeding dispersal after the breeding season that pushes Little Blue Herons well north and west of their core range (Rodgers and Smith 2012). It is impossible to know where these birds originated from, but, given the scarcity of records for Oregon and Washington, it was likely a long distance away. All Egret sightings in British Columbia are worth scrutiny because they are all considered rare in the Province (Toochin et al. 2013). This species is a wandering species and it will likely be found again the future in British Columbia. It can occur anywhere and should be photographed and properly documented if encountered.

1.(1) immature October 15, 1974-January 5, 1975: Bud Anderson, mobs (RBCM Photo 373) Judson Lake, Abbotsford (Weber and Hunn 1978)

2.(1) immature September 19, 1993: Margaret Clayton, Isobel McLeish, mobs (photo) Air Park Lagoon, Courtenay (Innes 1993)

3.(1) immature November 11-18, 2010: Scott Thomson, mobs (photo) Powers Creek, Westbank (Charlesworth 2011, Toochin et al. 2013)
4.(1) immature October 24, 2020: Andrea Chapman (photo) private property, eastern Fraser Valley (D. Cecile Pers. Comm.)

  

We wish to thank Barbara McKee for editing this article. All photos are used with permission of the photographer and are fully protected by copyright law.

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