About females

Female Bare-necked Umbrellabirds are the phantoms of the tropical forests of Costa Rica. Until recently, so little has been observed or documented regarding nests, nesting behavior, eggs and the raising of chicks by Cephalopterus glabricollis that any resources mentioning these topics all refer back to the same few papers that had been written nearly 35 years ago. Sadly, even the data collected on a single nest found over three decades ago is brief due to the early failure of the nest. Considering the fact that Costa Rica has a fantastic bird watching community, a plethora of well-trained guides and massive numbers of tourists entering national parks and reserves across the country, not seeing umbrellabirds on a regular basis is a telltale sign their numbers are extremely low.

Over the years, UCAN has located and collected data on over 30 nests, with many nests being active during our lengthy observations. Since all this information is new to science we have been very busy writing papers to be published in the near future. Once this had been accomplished we will be sharing the new data, images and videos regarding mating, nesting, brooding and chicks on this website.

Below you will find general information on the female as well as descriptions of behaviors we have witnessed during our study.

As mentioned, females remain silent throughout their lifetime, aside from a few throaty distress calls that have been observed during mating attempts (males can be quite aggressive and competitive). They hunt silently, hopping quickly along branches in pursuit of prey, or taking short flights from tree to tree searching for other food items. Fruits and seeds make up a large part of their diet most of the year. Though primarily a mid-canopy bird of mature forests, we have observed females collecting frogs, insects and fruits from the ground, as well as in small trees along the edge of secondary forests. At rest, females sit silently, preening and observing their surroundings. The best chance of spotting a female outside of her nesting area is to go to a suitable food source and wait. Whenever we start looking for Bare-necked Umbrellabirds in new terrain, we always follow our ears. If we are lucky enough to hear the wonderful BONK of a Three-wattled Bellbird (Procnias tricarunculata), we know that is a great place to start. We often find the males and females of both species feeding on the same fruits. Although umbrellabirds tend to be silent at feeding sites, bellbirds are not.

A keen eye is needed in order to find females in the forest. A very high percentage of the females we find are located when in flight. Female Bare-necked Umbrellabirds are similar in appearance to the males, aside from varying feather arrangements and the female lacking a well-developed vocal sac. Females are also smaller and lighter than the males, with females measuring ca 36-38cm and weighing in at around 310-325 grams during breeding season. When flying, Bare-necked Umbrellabirds show a distinctive profile unlike other birds found in their range, consisting of a very short, square tail and a strange, almost headless look in flight due to the heavy crest and short neck. While searching for females in our research area, we have been fooled briefly by the quick glimpse of a trogon, quetzal or even a black guan moving in the thick canopy as these are the only birds we encounter large and dark enough to consider as a possibility. No doubt our elevated anticipation of finding such an elusive bird helps in the trickery.

Female umbrellabirds are monotypic, showing no regional variations in appearance. In the hand, females show a beautiful dark brown eye, a strong corvid looking bill with small rictal bristles, large, elongated nostrils and a more brownish belly than the male. Females are more aggressive than males when first caught in a mist net. They hiss, growl and snap at anything coming close enough to grab. They have a powerful bite and will often refuse to let go once they have a good hold. They can easily draw blood if they hit their mark by using a repeated twisting and pulling technique with their bill. We have seen them use this action to twist off larger nesting materials and stubborn fruits.

If hunting in the same area for a long period of time with a silent observer present, some females have become quite relaxed and will venture within a few meters of the observer while foraging, provided you are not in close proximity of an active nest. Fruits make up a large part of her diet until the chick has hatched, at which time she focuses most of her time hunting for insects and invertebrates to feed her young, saving the fruits for herself.

Like the males, female umbrellabirds regurgitate most of the large pits and seeds contained within the fruits they consume. By placing nets at ground level directly under nests and lekking display branches, we have collected several thousand seeds from over 30 species of tree in just a few short weeks. Like the Resplendent Quetzal and the Three-wattled Bellbird, the Bare-necked Umbrellabirds are fantastic seed dispersers helping to keep the forest well stocked with a plethora of seeds needed to keep the forest diverse and healthy.