Variability of parental investment in lapwings of the genus Vanellus

Ing. Kateřina Brynychová

Doctoral thesis

Abstract:

Parental care in birds takes many forms and often requires the involvement of both parents. Although partners have the same aim to raise as many offspring as possible, their investment in parental care may differ, which can negatively influence the more involved parent. Therefore, communication or a kind of negotiation between the partners is important for successful reproduction. Parental care is not only energy and time consuming, but also difficult in coordinating the activities involved and risky due to the presence of predators. In this thesis, I investigated several aspects of parental care in the temperate Northern Lapwing Vanellus vanellus and the subtropical Red-wattled Lapwing Vanellus indicus. Both species are biparental, but with different lifestyles, and represent the genus of lapwings from the plover family, order Charadriiformes. First, I focused on parental exchange at the nest and related communication in the Northern Lapwing with highly variable male contribution to incubation. In our study, we found that the incubating parent can communicate with the non-incubating partner using acoustic and visual signals, which helps to synchronize parental exchange at the nest. Thus, communication and negotiation between partners play an important role in parental care in a biparental species with unequal parenting. Second, predation risk shapes the parental care behaviour. Ground-nesting birds use a variety of defence strategies to protect the offspring from predators, but little is known about a choice of strategy based on predator species and about the role of conspecifics in shared defence, especially in subtropical species. We experimentally confirmed that Red-wattled lapwings distinguish between different types of predators, and we found that both parents respond equally to the presence of predator and may share the nest defence with other conspecifics. Third, many of the parental services provided for the benefit of the offspring are costly as they are carried out at the expense of parents' self-maintenance. In addition, the level of parental effort of one sex may influence such a behaviour of the counterpart. Therefore, we analyzed the daily rhythms of sleep and feather preening of incubating Northern Lapwing females and showed that male incubation effort affects female self-maintenance behaviour on the nest. We also showed that the risk of predation modulates these behavioural rhythms. Fourth, decisions for fidelity or divorce in birds are species specific but are also influenced by environmental conditions. The subtropical environment provides a long breeding season, which allows multiple breeding within a year and therefore more opportunities for frequent mate changes. We were interested to see the preferred strategy of Red-wattled lapwings, i.e., whether they prefer mate fidelity or more frequent partner changes. Despite the potential benefits of divorce in some aspects, we found that Red-wattled lapwings exhibit extreme mate fidelity both within and between seasons. We have tried to explain this extreme mate fidelity. In sum, in this thesis I have investigated several aspects of shared parental care and the relationship between partners during reproduction in two biparentally breeding lapwing species. In particular, the importance of communication and cooperation between partners and other conspecifics during incubation period has been described and shown in detail, as well as the behaviours that can take place during incubation and in defence against predators. Whereas different roles of parental care are more divided between the partners in the Northern Lapwing, which may be related to partial polygamy of this temperate species, the parental roles are more equal in the Red-wattled Lapwing, which may be related to its extremely high partner fidelity and breeding in a hot long-seasonal environment.

Keywords

Northern lapwing, Red-wattled lapwing, parental care

Language used: English

Date on which the thesis was submitted / produced: 25. 1. 2024

Thesis defence

• Supervisor: prof. Dr. Mgr. Miroslav Šálek
• Reader: Jaroslav Cepák, Bc., externi, Tomáš Albrecht, externi, Tamá Szekely, externi

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Doctoral programme / field:
Ecology / Ecology