1. 1 Successive clutches and parental roles in waders: the importance of timing in multiple clutch systems DONALD BLOMQVIST, JOHAN WALLANDER and MALTE ANDERSSON

2. 2 Introduction Patterns of parental care vary widely among animal taxa, often also between closely related species. (Clutton- Brock, 1991) Much of this variation can be found within waders : in some species both sexes tend the eggs and chicks, whereas only one parent, either the male or the female, provides care in others. (Szekely & Reynolds, 1995)

3. 3 Rearing of several broods or litters during one season occurs in birds (e.g. Burley, 1980), mammals (e.g. Mendl, 1988) and fish (e.g. Potts & Wootton, 1984). Production of successive clutches within the same breeding season has received less attention than many other aspects of avian reproduction. (Burley, 1980; Tinbergen, 1987; Linden,1988; Verhulst & Hut, 1996)

4. 4 Material & Methods Temminck's stintmountain plover spotted sandpiperlapwing Kentish ploverringed plover stone curlew New Zealand Dotterel

5. 5 Results & Discussion Waders often produce a replacement clutch if the first clutch or brood is lost. (Cramp & Simmons,1983) Proper multiple clutches (produced even though the previous clutch has not failed) occur in some species. Three different breeding systems ： –double-clutching (uniparental care) –monogamous double-brooding (biparental care) –polyandry (uni- or biparental care) (Reynolds, 1996)

6. 6 double-clutching –polygamy by both sexes –female lays two clutches in rapid succession –distinct parental role division monogamous double-brooding –the same pair rearing two broods in succession polyandry –mate with different males –sex-role reversal –reduced or no parental care by females (Erckmann, 1983;Oring, 1986) (Erckmann, 1983)

7. 7 丹氏濱鷸 岩鴴

8. 8 double-clutching –polygamy by both sexes –female lays two clutches in rapid succession –distinct parental role division monogamous double-brooding –the same pair rearing two broods in succession polyandry –mate with different males –sex-role reversal –reduced or no parental care by females (Erckmann, 1983;Oring, 1986) (Erckmann, 1983)

9. 9 栗胸鴴 環頸鴴 石鴴

10. 10 栗胸鴴 環頸鴴 石鴴

11. 11 Double clutching has evolved via brood overlap in double brooding species. (Pienkowski & Greenwood, 1979; Erckmann, 1983; Blomqvist & Johansson, 1994)

12. 12 double-clutching –polygamy by both sexes –female lays two clutches in rapid succession –distinct parental role division monogamous double-brooding –the same pair rearing two broods in succession polyandry –mate with different males –sex-role reversal –reduced or no parental care by females (Erckmann, 1983;Oring, 1986) (Erckmann, 1983)

13. 13 東方環頸鴴 斑鷸

14. 14 Temminck's stint, Finland (TSF) Temmincks stint, Norway (TSN) mountain plover, central USA (MPC) spotted sandpiper, north USA (SSN) lapwing, England (LWE) lapwing, Sweden (LWS) Keritish plover, France (KPF) Kentish plover, Spain (KPS) New Zealand dotterel, North Island (NZD) ringed plover, Germany (RPG) ringed plover, Sweden (RPS) stone curlew, England (SCE)

15. 15 biparental care parental role division

16. 16 LWS LWE

17. 17 早 晚

18. 18 What determines the interval between clutches? between species The time available for breeding may be important. ex: Little Stint 、 Sanderling (Oring, 1986) The abundance and/or temporal distribution of food is important. There is a trade-off between the number of young in the first brood, and the timing and occurrence of consecutive clutches (e.g. Verhulst & Hut, 1996)

19. 19 Parents selection to produce the second clutch early if there is a seasonal decline in the reproductive value of a clutch. (Smith, Kallander & Nilsson, 1989) within species The ability to rear overlapping clutches increases as birds gain breeding experience. (Burley, 1980 ） Parents may initiate a second clutch as a response to a substantial reduction of their first brood.

20. 20 Conclusion Early laying of the second clutches are associated with parental role division and uniparental care There is a long time interval between clutches in species or populations with biparental care. Breeding season, food availability, number of first brood and breeding experience are the factors that influencing the relative timing of the second clutch laying.