African Wildlife & Environment Issue 84 2023

GARDENING FOR BIODIVERSITY

prolifically, losing some has only a minimal impact on seed production. In areas around the trees there is often a host of small specimens springing up, despite the destructive feeding habits of these flower ‘pirates’. Unfortunately, the many birds attracted to the flowers also include the Common Myna (Indian Myna). Not only plants are invasive aliens! In fact, these raucous creatures are included in the International Conservation Union’s list of most invasive species. Although they may evict indigenous birds from their breeding sites in tree hollows, mynas mostly breed in human-made structures, such as gaps in roofs or holes under eaves. So if you block up such nest holes, and make sure that mynas do not breed on your property, this will help to curtail their population growth. While some people find this member of the starling family comical or even lovable, it is a spiteful bird which has been observed to attack and chase away some of our indigenous species for no apparent reason. When their young are nearby, they can become quite vicious and, with rasping screeches, dive-bomb cats, dogs and sometimes even humans.The genus name Acridotheres is derived from the Greek words for ‘locust’ and ‘hunting’, and probably describes the bird’s way of hopping around while looking for food. The species name tristis , is Latin for ‘sorrowful’ or ‘depressing’. It presumably refers to its dull colouring or its facial expression, but is actually more applicable to its victims! Don’t for a moment get the impression that Erythrina species are lifeless when not in flower. Although less spectacular, all sorts of caterpillars are fond of munching the new leaves and they become welcome meals for many feathered friends. These include the larvae of no less than ten moth species. One of them is the Tailed Emperor Urota sinope , a large brown moth marked with white lines. Males have small tails on the hind wings, hence the common name. The larvae are gregarious during their early stages and have the strange habit of following one another head-to-tail in single file while waving the front half of their bodies in unison. After flowering, Erythrina trees and shrubs bear brown to black, knobby pods containing hard, shiny, red seeds, which are often referred to as ‘lucky beans’ and are popularly used for necklaces and other crafts. These seeds contain a curare-like muscle relaxing poison and have been used medicinally. Contrary to popular opinion, this poison is not fatal if taken by mouth because it is eliminated from the body faster than it is absorbed. However, on occasion, the seeds contain other poisons so it is not recommended

Most of the Erythrina zeyheri plant is underground. The spiny leaves and spectacular flowers only appear above the surface in summer, much to the delight of this Malachite Sunbird (Photograph: C Botha)

of this shrub. One of the most spectacular sights in any garden is to see a Greater Double-collared Sunbird visiting an Erythrina tree in bloom, as its chest brilliantly matches the flowers. However, sunbirds are not the only birds you will see in these handsome trees because a multitude of other species, not usually associated with nectar, will join the feast. Blackheaded Orioles often make themselves at home in a flowering tree, continuously filling the air with pretty, ‘liquid’ tones. At times, Redwinged Starlings arrive in droves to compete with various species of weavers for the best flowers. Interestingly, research has shown that different species of Erythrina are pollinated by different bird species. Vervet Monkeys and greedy Grey Go-away-birds (Grey Louries) eat the flowers of certain species whole but, because these are usually produced so Also with striking red to orange flowers, Sesbania punicea is an invasive alien plant: beautiful but dangerous to the natural environment! (Photograph: S Woodhall)

44 | African Wildlife & Environment | Issue 84 (2023)