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Hornbill Guano (scat) by Asha Bertch

Field Naturalist : Ajantha Palihawadena

Research and report : Asha Bertch

Sponsored by : EarthRestoration and Belipola Applied Bio-Research Institute


14 August 2020 @ Belipola Arboretum:


The female hornbill has emerged from her maternal hibernation—a home, made within the hollow of an old tree. Over the past three months she has incubated and hatched chicks while her mate has foraged the analog forest selecting the most nutritive seeds, berries, and insects and choice lizards to bring up the next generation. We watch daily as the male makes routine visits to the tree, regurgitating berries, his beak disappearing into the hollow. Where does he go when he flies off? What is happening inside that tree? Ajanta Palihawadena gets the great idea to answer these questions by examining the scat deposited at the base of the tree. I take it upon myself to do the dirty work, and as organically as anything that happens in a forest, a research investigation is set into action.



I spend a bit of time carefully sweeping up all 3-months’ worth of scat and collecting it onto a woven tray. The following few hours, I sift the contents, picking apart and organizing all the tiny iridescent insect parts onto one collection tray, and all the different seeds onto another tray.


Dissecting the scat, I find seeds of about 10 distinct species of trees and the body parts of a wide diversity of insect species. Of these, some are immediately identifiable as seeds from kithul (Caryota urens), beeriya( Litsea ovalifolia), and sapu (Michelia champaca) trees, the wings of a damsel fly, the heads of a yet to be identified lepidopterae, and what looks like the thorax of some kind of grasshopper.


Our task now is to identify the remainder of these species and to find where they are existing within the analog forest.The forest tells us many things with each simple message. The scat left by the female gives us a map of where her mate has been— how far he has traveled to find food for her, what elevation in the canopy he frequents most to collect berries, and where he most likely hunts for insects. It tells us which forest berries she prefers, and of these, which are her favorite—a small, dark brown and flattened seed is abundant, making up about 40% of seeds found in the scat, while those of the sapu are few (less than 5%). About 25 % is made up of a yet to be identified ficus species. Kithul and beeriya make up about 15% each, the seeds of a palm species make up another 10%, and the remaining 5% is an assortment of unidentified seeds present in numbers as small as one or two. It also tells us, without traveling too far, which trees have been producing fruit at present, over the past few months, and what will be coming n the near future.


The female has left the nest and now begun to help the male forage food for their chicks. The chicks will remain in the nest for a while still. This gives us time to observe their foraging patterns, and any changes in diet that might occur. Changes in season may influence the availability of different forage sources. Perhaps as the chicks mature, their metabolism will require more robust food sources. These are questions we can continue to address and monitor. We will collect from the base of their nest tree and document the wide range of forest forages they consume up until the chicks leave the nest.


And what will happen to the scat samples we collect over the duration of this study? As residents of the forest, we know this is not simply research material, but an invaluable resource created by and belonging to the forest. Birds are the great tree planters of our planet. These discarded seeds have been softened and dormancy mechanisms disarmed by their passage through the gut of the bird. The scat itself is a nutrient rich encasing that will provide ample fertilizer for the emerging seedlings. As the hornbill tosses these materials from her nest, she plants her own forage-specific analog forest outside her home, just as we are learning to do.

Above : Ongoing research at Belipola


We will be sure to do her this service. After analyzing the scat and identifying the floral and faunal diversity of its contents, we will take and plant the discarded materials of the nest. Paying close attention to what grows out of this, we will be able to identify some of the lesser known species of seeds as they grow into the plant forms we are more familiar with. Planting the hornbill scat not only aids the depth of our research, but in doing so we simultaneously facilitate the establishment of an analog forest, designed by the preferences of the hornbill herself, and available to the generations of hornbills to come.


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