Hybrid Snowy Egret X Little Blue Heron at Burnham Prairie Nature Preserve

By Randy L. Shonkwiler

When David Gruver reported a hybrid Snowy Egret X Little Blue Heron at Burnham Prairie Nature Preserve on 22 June 2021, I noted that it was interesting. However, being that I do not own a car and the fact that the bird was a hybrid, I didn’t make any effort to find someone to take me to see it. My attitude changed dramatically when Tracy Weiner photographed what is likely the same bird on 21 July on Jackson Park’s Wooded Island, which is my own birding patch! I received Paul Clyne’s report of the bird the next day but couldn’t get to the park until the 24th due to work and other obligations. Still, I didn’t get up at the break of dawn, because I was going to go with Jeff Skrentny and Paul Sweet for mothing (my first time) at Kankakee River State Park and wouldn’t return home until 2:00 am. I didn’t get to the park until after 8:30. Paul Clyne asked me where I’d been as I joined him and several others to see the bird in the Garden of the Phoenix (formerly Osaka Garden). Jeff and Paul were able to see the bird later when they came to pick me up.

Fortunately, the hybrid was still in the park as of Saturday, August 14. It was not seen on the weekend previous but was foraging near the Music Court Bridge all day on the 14th. The attraction for the hybrid seems to have been many small silvery fish in the koi pond of the Japanese garden. But it wasn’t just the hybrid that was attracted. Over the last few weeks, we’ve been getting up to 15 Great Blue Herons, 5 Great Egrets, plus several Black-crowned Night-Herons and Green Herons in the park every day, with most of them periodically visiting the koi pond to feed on the little fish! The best fishing spot was the walking stones in front of the waterfall. Competition for this spot could get intense! The Snowy Egret X Little Blue Heron was often bullied by the bigger herons. At one point I saw a 2nd year Black-crowned Night-Heron chase off the hybrid but it was then immediately chased off itself by an adult Black-crowned Night-Heron. The hybrid usually took refuge in a large maple tree behind the waterfall. I speculated, half-jokingly, that they had stocked the koi pond with these fish to keep the herons from eating all the koi fish (which happened one year), but Park District biologists Lauren Umek said that they the Park District did not stock them.

Paul Clyne noted that this bird looks superficially like a 1st spring Little Blue Heron, often called a “calico,” with its patches of blue-gray on white. He noted that the Snowy Egret features include the slaty legs, yellow feet, yellow lores, all black bill and shaggy crest. While reviewing photos of the bird at Burnham Prairie I noticed that it appeared to have a dark lores and dark feet unlike the Jackson Park bird. However, after discussing this with Paul, we agree that these parts may have turned yellow in the time between sightings (plus the feet might be dirty in the earlier photos) and Paul noted that the patterns of the white and blue-gray feathers are too similar for the Jackson Park bird not to be the same as the Burnham Prairie bird. The shaggy mane/crest (Snowy Egret feature) indicates an adult, but I noticed in some photos that the bird has yellow-green up the back of the legs which is usually found in juvenile Snowy Egrets.

The pairing of Snowy Egret with Little Blue Heron is rare but seems to occur regularly. The earliest documentation of hybridization between these species that I can find is a bird seen and collected at Lake Okeechobee in Florida in January and February 1953. It was sent to the “U. S. National Museum” (Smithsonian?) and confirmed as a hybrid Snowy Egret X Little Blue Heron (reported in The Auk, vol. 71, no. 3, p. 314 by Alexander Sprunt Jr.). I found a few recent records on eBird (this wasn’t easy! I had to do a search on the internet, because eBird wouldn’t let me search for a hybrid and yet, when I did the internet search the first result was eBird’s “species” account for Snowy Egret X Little Blue Heron, and then I had to look at the locations of the photos posted to eBird, most of which were the Jackson Park bird!). Hybrids were seen in Colbert, Alabama on 21 May, 2018 and again on 19 April, 2019 (not sure if this was the same bird wintering over), at South Nags Head, N.C. on 27 January, 2005, at Salt Lake WMA, Brevard, Florida on 28 October, 2006 and also at nearby Merritt Island NWR on 6 April, 2018, 1 May, 2020 and 22 March, 2021, Kendall, Texas on 26 March and 26 October, 2021 (maybe the same bird?) and Cumberland, Maine on 18-19 August, 2020, among other sightings. One difficulty with identifying the parentage of these birds is that there are Snowy Egret hybrids with Tricolored Heron. While I do not see anything that screams Tricolored Heron X Snowy Egret, it may be something that the IORC would want to consider.