Diet of Swift Tern Chicks in the Saldanha Bay Region, South Africa

Abstract

The diet of the Swift Tern Sterna bergii was investigated over a ten-year period off the west coast of South Africa by collecting re ur itations from chicks dunng ringing operations. A total of 1 31 1 prey items of 25 identifiable species (d ofwhich were fish) was collected. Fish formed 86 % of all the prey items. Other prey species included cephalopods, crustaceans and insects. 60% by number of prey taken consisted of pelagic shoaling fish, of which Cape Anchovy Engraulis japonicus occurred most frequently and was the most abundant prey species in seven of the nine years in which samples were collected. Weekly collections in 1984 confirmed that pelagic shoaling fish, in particular Cape Anchovy, were the most abundant rey mass.taken during the chick-rearing period. Prey size varied from 7 to 138 mm in length and from 0,l to 30, B gin

Comparative foraging ecology of five sympatric terns at a sub‐tropical island in the eastern Indian Ocean

“…For instance, Hawaiian seabirds ate 74 species of fish from 56 families (Harrison et al, 1983) and sooty terns and brown noddies at the Dry Tortugas, Florida, consumed 84 species from 33 families (Hensley & Hensley, 1995). In contrast, crested terns in South Africa (33 • S) consumed only 20 fish species (Walter et al, 1987). This compares with the 51 fish species from 35 families taken by the terns in this study.…”

“…Percentage mass, sometimes estimated from length/mass formulae, is also a common measure used in dietary studies (Croxall & Prince, 1980;Walter, Cooper & Suter, 1987). In this study, limited data on the prey species length/mass ratios, and the fragile nature of most regurgitates precluded using percentage mass for estimating volume.…”

Distribution, population structure and biology of stomatopod Crustacea off the west coast of South Africa

“…1987), sharks, and a variety of reef fish (Nepgen 1982). Of the seabirds, they are taken in considerable numbers by jackass penguins Spheniscus demersus (Rand 1960a) and to a lesser extent by Cape cormorants Phalacrocorax capensis (Rand 1960b), Cape gan nets Morus capensis (Rand 1959), bank cormorants P. neglectus and swift terns Sterna bergii (Walter et al 1987).…”

Seabird consumption and production in the Benguela and Western Agulhas ecosystems

“…In the open-sea environment kelp gulls eat macrozooplankton when abundant, prey on fish, scavenge fish discarded by trawlers, kleptoparasitize other seabirds, notably Cape cormorants, feed on the carcases of South African fur seals and prey on the eggs and nestlings of seabirds breeding at islands (Shelton et al 1978, Sinclair Brooke andCooper 1979, Shaughnessy 1980). Hartlaub's gulls feed primarily on macrozooplankton, but they occasionally take mesopelagic fish when these are easily available (Walter 1984, Walter et al 1987a, b, Ryan 1987. The diet of greyheaded gulls was assumed similar to that of Hartlaub's gulls, but with a higher proportion of shoreline (including freshwater) items.…”

“…1990, Crawford et at. 1985, Walter 1984, Walter et al 1987a. For great and crowned cormorants, information was gleaned from Rand (1960b).…”