Does Cattle Egret have a dark morph?

    → Last Updated on

On 18 May 1987, while birding at Cape May, NJ, I came across a small group of Cattle Egrets foraging in a field. Accompanying them was the bird in the photos below. In shape and behavior it was identical to all of the other Cattle Egrets, but its head and neck were mostly dark grayish.

Dark Cattle Egret, Cape May, NJ, 18 May 1987. Photo copyright David Sibley.


I ruled out the possibility of a hybrid, since it looked identical to the other Cattle Egrets in every respect except color. I ruled out the possibility of staining because the feathers seemed to be in excellent condition, dry and smooth. The contours of the bird, the sheen of the feathers’ surface, the “loft” of the feathers, all appeared perfectly normal. Furthermore, it would be a very odd pattern of staining – dark on the neck, breast, and primary coverts, but white on the face and most of the wings. I was satisfied to call it a melanistic or dark morph Cattle Egret.

 

Over the years I’ve heard of several similar individuals. The species account in BNA mentions reports from South Africa, Florida, and Illinois (Telfair, 2006). A Google search reveals additional reports from Nigeria, India, Spain, Portugal, Morocco, Barbados, Dominica, Florida, and California (see references). Excellent photos of the Nigeria, Barbados and Dominica birds can be seen in links below.

Most often the color has been dismissed as “staining”. Apparently Cattle Egrets are sometimes stained when crude oil or other chemicals are sprayed on crops such as citrus trees in Florida, and birders there report seeing oddly colored Cattle Egrets “a few each year” (Rich Paul, pers. comm.). These birds, however, are generally stained greenish or brownish, and also look disheveled. The matted feathers create gaps in the contours of the body and cause the bird to persistently preen the dark spots. I did not see any sign of that, and concluded that gray was the natural color of these feathers.

In the case of the Dominica bird, which was seen over a period of nearly three months, the color was darkest and most extensive when first seen, and was observed to “fade” over about three months. At least some of this fading could be the result of powder down, which turns blackish feathers to gray. ((Powder down is a specially modified feather that disintegrates into a talcum-like powder. A few families of birds have powder down, which is thought to be used along with oils for feather care.))

The Dominica bird and one of the Nigerian birds appear to be juveniles, but many of the others (seen in spring or summer) must be at least a year old, and the South  African bird appears to be an adult.

Arguments for staining (or for melanism)

  • Some feathers appear to be sticking together as if stained (but most feathers appear normal, dry and smooth)
  • The underside of the feathers appears paler (but this is a common natural pattern of feathers, and difficult to confirm, and one Dominica photo shows an entirely dark gray underside of the outer primary just like the upperside)
  • The feet appear to have some similar kind of grey coloration (but feet and bill could be affected by melanism just as the feathers are)
  • Some feathers of the Barbados bird appear dark tipped with a pale base as if each was protected from staining by an overlapping feather which has since been molted (but many species of birds show a similar color pattern naturally, and some of the wing coverts of the Barbados bird appear to be dark with pale tips)

The staining hypothesis seems to leave two major inconsistencies.

  • If this is staining, how can it account for the all-dark primaries shown by the Dominica bird? Those feathers should have been well-protected from any external source of color.
  • If this is staining, why is it seen in only a few Cattle Egrets, at widely scattered locations? Why not in clusters of multiple individuals or in other species such as egrets, White Ibis, etc?

Until one of these birds can be closely-studied, ideally in the hand, the true source of these dark feathers will remain a mystery, but for now my guess is that they represent a very rare melanistic morph of Cattle Egret.
[portfolio_slideshow]

References

Kempenaers, B., K. Delhey, and A. Peters. 2007. Cosmetic Coloration in Birds: Occurrence, Function, and Evolution. The American Naturalist 169, Avian Coloration and Color Vision, pp. S145-S158  http://www.jstor.org/stable/4125308

Pyle, P, and S. N. G. Howell. 2004. Ornamental Plume development and the “Prealternate molts” of herons and egrets. The Wilson Bulletin 116:287-292.  http://www.bioone.org/doi/abs/10.1676/04-012?journalCode=wils.1

Siegfried, W. R. 1971. Plumage and moult of the Cattle Egret. Ostrich suppl. 9:153-164.

Telfair II, Raymond C. 2006. Cattle Egret (Bubulcus ibis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/113

Other reports

Illinois

Peterjohn, B. G. 1987. Middlewestern prairie region (nesting season). Natl. Audubon Soc. Am. Birds 41:1440-1444.  http://elibrary.unm.edu/sora/NAB/v041n05/p01411-p01495.pdf

Lake Renwick, IL. summer 1987; one bird in small breeding colony “entirely gray with normal adult leg and bill color”

California

Imperial Valley, CA, Feb 2007.

Melanistic Cattle Egret – “A dark, off-color cattle egret has been foraging on the north lawn at Imperial Valley College for the past two afternoons.”

Florida

Loxahatchee NWR, FL – http://bna.birds.cornell.edu/bna/species/113/galleries/photos/CLW_CAEG-FL_Loxahatchee-NWR (subscription required) very pale gray on body, unlike others.

South Africa

This is the darkest of the several birds photographed, presumably over the next few months this bird will fade to the smooth gray shown in other photos and will begin to replace these feathers with white ones? http://www.birdinfo.co.za/rarebirds/25_avian_colour_oddities.htm

Egret,melanistic,melanism,bird,birds,animal,animals

Nigeria

two different individuals

http://www.flickr.com/photos/seth_of_rabi/2817072368/ – 31 Aug 2008 – apparently juvenile

http://www.flickr.com/photos/seth_of_rabi/3047832119/ – 21 Nov 2008

Barbados

Graeme Hall Swamp, Christ Church, Barbados, 19 September 2002

http://secrb.trinidadbirding.com/bacattleegret.html

Dominica

Aug 2009 – all blackish

discussion here http://www.birdforum.net/showthread.php?t=145867

photo here (registration required) http://www.birdforum.net/gallery/showphoto.php/photo/265831/limit/recent

3 Oct – white head and neck, paler gray body http://www.birdforum.net/gallery/showphoto.php/photo/273382/limit/recent

23 Oct – gray only on wings and tail http://www.birdforum.net/gallery/showphoto.php/photo/276539/limit/recent

same bird – note dark bill tip and dark legs

23 Oct 2009 Dominica

http://www.pbase.com/tmurray74/image/118815082

http://www.pbase.com/tmurray74/image/118815083

Spain

Herkenrath, P. 2002. Another melanistic Cattle Egret. British Birds. 95: 531 – 531.

Observation of a melanistic Cattle Egret in southern Spain on 2 May 1993.

Portugal

Scheres, W. 2002.  A partly melanistic Cattle Egret Bubulcus ibis. A Rocha Portugal Observatory Report 2002 15. http://www.arocha.org/pt-en/413-DSY/version/default/part/AttachmentData/data/pt-report-2002.pdf

With black head and neck, dark gray breast, other parts normal; seen several times Aug 2002 in a rookery at A Rocha, Portugal

Morocco

June 2007

http://www.valeryschollaert.com/index.php?option=com_joomlaboard&Itemid=175&func=view&id=417&catid=2

India

Willoughby, P. J. 2001. Melanistic Cattle Egret. British Birds, 94: 390 – 391.

An observation of a grey Cattle Egret [Bubulcus ibis] at Dona Paula, Goa, India, on 19 November 1995.

19 thoughts on “Does Cattle Egret have a dark morph?”

    1. Thanks for the link Jerry. That does look very similar, and it could all be staining of some kind, although the gull seems to show a more “scruffy” and blotchy pattern than the egrets, but that’s just grasping at minutiae. It’s hard to believe there could be two different explanations for this – one for the egrets and one for this gull. It would be good to hear of any other similar cases.

  1. Hi David, I’ve uploaded to this URL (http://bit.ly/lp09CR) another sighting of a melanistic Cattle Egret, this one from Yemen. Ornithological Society of North Yemen Newsletter 1986 2(2): 10-11. A melanistic Cattle Egret observation by S. Fairman from Yemen on 20 March 1986. It seemed to be adult, it was nest-building and had chestnut plumes, etc., tho the bill and leg colour were not as bright and striking as its neighbours in the colony.

  2. I live on the island of St. Kitts in the Eastern Caribbean. I have now twice seen an all-black cattle egret, both times near our house in Frigate Bay. I have tried to get pictures, but have not yet succeeded.

  3. Bryan Boshart

    I live west of Houston, TX. Please excuse my lack of knowledge of terminology. Twenty or thirty black/gray cattle egrets fly over my house every evening this time of year, along with maybe 400 white ones. I’ve noticed it for 3 years now. Most fly with the white groups, others fly in their own groups of 3-6, and some solitary ones trail the white groups. They are definitely not the same as the bigger herons that pass by. The shape, rate of wing flapping, and flight pattern is identical to that of the white cattle egret, although they may be about 5% larger. I’ll try to get pics.

    1. Hi Bryan, It would be extremely unusual to see that many dark Cattle Egrets. I wonder if you could be seeing a few Little Blue Herons among Snowy Egrets? Photos should sort it out, even distant snapshots, just enough to show the proportions of legs and wings.

      1. Bryan Boshart

        OK thx David, I’ll try to post pics in the next few days. I haven’t seen snowy egrets (I think), but plenty of white ibis and great white egret? The ibis typically have cattle egret mixed in. I’ll photograph them directly overhead, so you can see the legs straight out. At least 800 birds last night, about 25 little dark ones.

    1. Hi Bryan, Thanks for the photo link, sorry to be slow replying. I would say the dark birds are Little Blue Herons. They look a little too long-legged for Cattle Egrets, and they are entirely dark, whereas all of the dark Cattle Egrets seen to date have white wings, just dark gray blotches on the neck and body. The white birds are more challenging to identify. It’s possible that some of the white birds are immature Little Blues, but at this date they should be showing some dark adult-colored feathers, and should probably be less numerous than the adults. The proportions look good for Cattle Egret (short legs) but they seem a little larger than the Little Blue Herons. So I think the choice would be between Cattle Egret or Snowy Egret, and the main differences are leg length, foot color, and bill color.

  4. Carmen Alvarez Thibodeaux

    I had encountered this egret, which I feel is a morph as well at Jefferson Island, Louisiana. I had sent this photo to Erik Johnson, ornithologist at LSU and provided me with this article and thought I should share this with you. Please let me know what you think.
    Thank you.
    Carmen Alvarez Thibodeaux

  5. There are morphs to the white cattle egret. The ones I’ve seen in Louisiana soybean and rice fields look the same as the white ones except they are dark blue or black or dark grey. The male birds have the same gold plumage as the white ones. They are very pretty birds but not very common and may be a genetic mistake. I wish I had a photo to add.

  6. This morning, February 15, 2016, I saw a flock of 22 Cattle Egrets in San Benito, Texas. They were following a tractor cutting grass. One of the 22 looked exactly like the picture at the beginning of this post. I did not have my camera with me. But I had my binoculars and was quite close to these birds. I thought it looked odd and went home to get my camera. When I returned, they had disappeared.

    1. Hi Jennifer, Thanks for sending these photos. I really can’t say whether these are stained or natural, the debate is ongoing. The fact that you found two very similar birds together is remarkable, but doesn’t support one side over the other. I can see details in the feathers of these birds that seem to support natural coloration (the blended gray-brown tips of some feathers e.g. on the greater coverts of the left bird, and the fact that both birds have a very similar dark mark above the eye). But other details seem to support staining (the messy “matted” look of some of the dark feathers, especially the bird on the right). If you have more photos, and higher resolution, that would be interesting to study. One thing I would like to know is whether the dark markings are similar on the right and left sides of each bird. That wouldn’t solve the mystery, but symmetrical would suggest natural. So if you have photos of the head or body turned the other way that would be great. Feel free to post more links here in the comments, or send links or photos directly to me through the “contact” link above.

  7. Lawrence F Gardella

    Last month on Kauai I saw a bird in with Cattle Egrets that was extraordinarily buffy with an almost pink cast. When it flew it showed wings that were all white, making it look much like a Squacco Heron, a bird that would not be expected on Kauai. I thought there was some blue on the bill, but it was partially obscured and too distant to be sure. The bill also appeared to show some orange. I have communicated with the North American Birds editor for Hawaii (also an ebird editor,) Lance Tanino, who believes I observed and poorly photographed a dirt-stained bird. Probability supports him.

    In this post about unusual Cattle Egrets you say “If this is staining, how can it account for the all-dark primaries shown by the Dominica bird? Those feathers should have been well-protected from any external source of color.” I take that to mean that you believe that a stained Cattle Egret would typically show white wings in flight. If that is so, that is all the more reason to believe that I saw a stained Cattle Egret. I would appreciate your comments.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.