Reproductive Strategies in Shorebirds
: (Alternative Format Thesis)

  • Claire Tanner

Student thesis: Doctoral ThesisPhD


Reproductive strategies are important aspects of adaptation which can influence breeding success in different environmental settings. My PhD thesis investigates shorebirds (sandpipers, plovers, and allies) that exhibit an unusual diversity of reproductive strategies among birds. Previous research has concentrated on northern hemisphere shorebird species, which could have different responses to reproductive strategies than species in southern hemisphere. In Chapter 1, I introduce reproductive strategies and reproductive decisions, first for all birds and then for shorebirds specifically. I highlight the importance of shorebirds as a study species, and detail my thesis focus and objectives. In Chapter 2, I found that nest survival in relation to clutch size was significantly different within three Malagasy species (Kittlitz’s, white-fronted and Madagascar plovers). There was no difference between species, suggesting that variations in nest survival rate are more affected by extrinsic factors than breeding strategy differences. In Chapter 3, I found that in these same three species of Malagasy plovers the parents may attend their young for up to at least 71 days. The three species varied in duration with white-fronted plovers providing less care than Kittlitz’s and Madagascar plovers. Only hatch date predicted the duration of parental care with a correlation between earlier hatching dates and longer parental care. I discuss the possible explanations as to why extended care is provided in these species, including social learning (of foraging areas or anti-predator displays), reducing predation to the chicks (from anti-predator displays or parental knowledge of predators), and increased survival for juveniles surviving their first year (from reduced predation and increased feeding opportunities from social learning). In Chapter 4, I found smaller broods produced more male offspring, and different habitat sites produced different sex ratio biases in Madagascar and white-fronted plovers (but not in Kittlitz’s plovers). This suggests that variation displayed in these two species is a function of brood size as well as the conditions that the brood experiences. This could be important for conservation efforts as it highlights that larger broods are preferrable for a higher female proportion of chicks, and that both fragmented habitats and large salt marsh areas are important to achieve parity in the overall population sex ratios of juveniles. In Chapter 5, I found that substitution rates and life history traits in bird species are correlated since age at first breeding (p < 0.05), clutch size (p < 0.001) and body mass (p < 0.001) predict substitution rates at both a species and family level. These results suggest that multiple life history traits are predictors of high substitution rates. Chapter 6 discusses the main findings of my thesis, relates this to the current trends in shorebird research, discusses reproductive strategies in a wider context and finally suggests future directions for shorebird research.
Date of Award29 Mar 2023
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorTamas Szekely (Supervisor)


  • reproductive strategies
  • Mating systems
  • breeding system
  • clutch size
  • parental care
  • parental cooperation
  • sex ratio
  • evolution

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