BirdWalk Newsletter 7.23.2017 Magnolia Plantation and Gardens Walks conducted by Perry Nugent Newsletter written by Jayne J. Matney Cover photo by John Nickerson “When the weather is hot, keep a cool mind. When the weather is cold, keep a warm heart.” Ajahn Brahm There is no doubt here at Magnolia Plantation that the spring has turned into summer. But something else that is absolute is the fact that true birders don’t stop for heat, cold, storms, humidity, etc. There are some wonderful things out there to see these summer months. This week’s article is about two types of birds that happen to be on many bird watchers’ “lifer” list even though they are fairly widespread in North America and can be found here on our plantation. The reason for being on a difficult-to-see list? They are very elusive. Not only are they extremely shy, but they have tactics and camouflaged coloring that make them difficult to see. If you haven’t guessed already, I am speaking of the American Bittern and Least Bittern. There are similarities and differences between these two types of bitterns and they are definitely worth taking an investigative look at them together. American Bittern (Botaurus lentiginosus) Least Bittern (Ixobrychus exilis) Photo by Susan Bailey Photo by Nick Verducci The two types of bittern found here in South Carolina, the American Bittern and the Least Bittern, fascinate us for many reasons – mostly because of the fact that they are so elusive and therefore, they represent a mystery to us. Hiding from us is an art for them. A special feature article in the BirdWatching Daily (12-28-2009) by Chris Duke called “How to Find American and Least Bitterns” champions those that want to find these special birds. Duke recommends listening to the recorded sounds made by the birds first and know how to recognize the vocalizations before going out into the field. This is because you may have better luck finding them if you can recognize the sounds first and then you will know where to look for them in the grasses. The time of day is also a key factor. Dawn, dusk, and night time hours are more likely to reveal their vocalizations. Keep in mind that the best time frame for vocalizations will be at the early portion of their breeding cycle rather than the end of it. Secondly, be knowledgeable about where to find them. Both types of bittern prefer fresh water ponds and marshes inhabited by tall grasses and reeds. Although the American Bittern is more likely than the Least Bittern to search for the more wide open spaces provided by large refuges, their ranges do overlap. Thirdly, Duke also provides some insight into seasonal timing. The birder needs to make sure of searching for them at the right time. They are most visible when active during the breeding and nesting time period of their annual cycle. Some bitterns are year round residences in the more southern parts of their ranges, but most migrate to areas that do not have weeks of frost during the winter. American Bitterns start breeding a season sooner than the Least Bittern, so if you are conducting your field search in a breeding habitat, look for them prior to the Least Bittern. Most agree that the American Bittern is seasonal between March to May, while the Least Bittern appear later, May through August. But this schedule varies somewhat according to geographical location and migration. Duke concludes with his suggestions by warning watchers away from actually tromping through the grasses to come upon these birds. This will encourage them to evacuate the areas or not choose this area to nest. Instead, use dikes, trails, and boardwalks or even kayaks to quietly maneuver within their area to encourage sightings of bitterns. The American Bittern will not cling to the edges of the grasses quite as much as the Least Bittern. Instead, the American Bittern will venture out a bit further out of the grasses and wade along the shallow waters for food. The Least Bittern will stay close to the grass edge and have the remarkable talent for bracing themselves between two grass stalks and with spread legs will suspend themselves between them and strike for food from above. This practice enables them to stay in the cover of the grasses but allow them to fish in deeper channels than the American Bittern. The best time to actually see the bitterns is during brooding season when gathering food for young becomes a top priority, and therefore increasing their activity. Least Bittern Photo by Guenter Weber Recognizing these birds can be tricky. Shy and fleeting, bitterns will sometimes make you think maybe you imagined them! The American Bittern is larger than the Least Bittern. Similar to a comparison between the Black-crowned Night Heron and the Green Heron, but Least Bittern are even smaller than the Green Heron. In general, bitterns have shorter legs than others in the heron family. Bitterns’ coloration and behavior sometimes go hand- in-hand. This is because their coloration and behavior are instruments for being undetected. Both types of bittern are described with buff, brown and white colors. However, the American Bittern and the female Least Bittern are similar as well in the dramatic striping along the length of the neck and body. This coloration and pattern help the bitterns to camouflage into the grasses. Not only that, these funny birds take this use to the maximum. When they sense danger (as in “humans are looking for me”) they will freeze in mid-step then throw their gaze up to the sky with beak upward and neck stretched (Thus, the nickname of “sky- gazer”). This makes them look more like the skyward growth of the grasses. Not only that…. they have actually been seen swaying like the grasses in the breeze! Least Bittern Photo by Guenter Weber The American Bittern and the female Least Bittern are sometimes confused with juvenile Black-crowned Night Heron and the juvenile Yellow-crowned Night Heron. So be watchful when identifying them. The male Least Bittern is sometimes confused with a Green Heron because the male Least Bittern has a dark brown/black crown and back which extends down to the tail having a greenish hue. They also have orange-brown to chestnut sides and chest. The face and neck can also have some chestnut. All of this coloration may make you suspect it to be the Green Heron at first. A detailed description is available at www.heronconservation.org under “Least Bittern”. Reviewing the differences with the use of a field guide prior to going out may help you feel more confident when in the field. Always remember that the Least Bittern are considered the “tiny” herons here. A bittern’s diet consists of mostly fish and insects such as beetles, giant water bugs, striders, grasshoppers, and dragonflies. Crustaceans such as crayfish are also in their diet as well as frogs, tadpoles, and small snakes. As stated earlier, the two types do forage differently for these delectables. American Bittern and Least Bittern definitely have different vocalizations. What they do have in common is the behavior of gulping air until their bodies swell then make loud drumming or pumping noises from the chest and neck (thus the other nicknames of “thunder pumper”, “stake driver”, “water belcher” and “mire drum”. More often heard but not seen, it is very rare that humans get to witness this behavior and vocal exhibition. Photo left shows “swelling” before vocalization. American Bitterns are known for their booming sounds, “oonk-a- lunk”, and “kok, kok, kok”, while the Least Bittern is more associated with low pitched cooing, clucking, or shrieking. They are not very social birds, staying away from others usually, however, some territorialize by approaching each other in a Photo by Susan Bailey crouching position and puff out their shoulder feathers. If either one persists in moving into the other’s territory, a match-up occurs with an aerial battle of beak jabbing. The American Bittern and the Least Bittern males differ in nest building and parenting skills. The American Bittern male does nothing. The female American Bittern does all of the nest building, incubating, and raising of the young. In contrast, the Least Bittern male is the primary nest builder, helps incubate the eggs, and assists in the feeding of the young. The nests are also different from each other. The American Bitterns’ nest is more of a platform design over the water made out of dead reeds and grasses. The Least Bittern uses the grasses which are still in place by bending them downward to make a platform between the stalks. They will then finish the nest off with some dead sticks and grass. The American Bittern lays beige-brown to an olive color eggs. The Least Bittern lays eggs which are very pale blue or pale green or even whitish. The clutches can be anywhere from 2-7 but usually 4 or 5 eggs. The publication, Heron Conservation, sites that research done shows that clutch sizes vary according to geographical location within the breeding range. In South Carolina, we fall into the average clutch size of 3.8. Once the eggs hatch, the young develop strong legs and feet rather quickly and staying in nests only for about 2 weeks. Conservation-wise, it is very difficult to conduct population studies due to their elusiveness. However, the American Bittern is showing a serious decline in much of the United States and Canada. The Cornell Lab of Ornithology states that, according to the North American Breeding Bird Survey, there has been a 43% decline between 1966 and 2015, but was not placed on the 2016 State of Birds Watch List.