LEBRET T (1976) Attacks by Avocets Recurvirostra avosetta on Shelduck Tadorna tadorna. LIMOSA 49 (1): 17-23.

Attacks by Avocets with young on Shelduck pairs without ducklings on a non-tidal brackish marsh in Zeeland province, the Netherlands, in the period 20th May - 10th June 1973 and 1974 are described. Some features of these attacks are shown by photographs. 2. An attacking Avocet nearly always selects the female of the pair and probably does so because of its smaller size. Attacks by Avocets on Sh.eldrakes are much less frequent than those on Shelduck females and Sheldrakes in contrast to ducks do as a rule not give in. 3. The position of the Shelduck in relation to that of the young Avocets is dealt with. 4. The biological significance of the attacks might be that the Avocets drive the Shelduck away from their young to hold a free view on the latter. 5. Both time and space may be a factor leading to these attacks. The majority of the Avocets has young some 3 weeks before the majority of the Shelduck. The marsh concerned is a concentration area of non-breeding Shelduck and moreover Shelduck with young tend to spacing out and to favour somewhat deeper water than young Avocets do. Hence attacks are less frequent later in the season Pied Avocet Recurvirostra avosetta Common Shelduck Tadorna tadorna

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