Phenology
Timing of breeding
Birds time their egg laying such that there is enough food available for their offspring when they need it most. However, to do that they need to be able to make an estimated guess about what the future brings: As an example, in blue tits, egg laying takes about 2 weeks, incubation as well, and the chicks have their highest nutritional needs at about 7-12 days of age. So a female needs to time their egg laying about 5 weeks before the environmental conditions are right. What cues do they use? What influence does climate change have on this? How phenotypically flexible are females?
We use quantitative genetic methoes to answer these questions.
Oak phenology
Oak trees provide food to herbivore insects, which in turn are prey to blue tits. This food chain is important because the bud burst of oaks is reliant on weather and climate, while blue tits likely use other cues for their timing of breeding. We use a long-term, detailed database of oak tree phenology to study the phenology of budburst.
Papers
Chik HYJ, C Estrada, Y Wang, P Vijendra, A Lord, J Schroeder. 2022. Individual variation in reaction norm but no directional selection in reproductive plasticity of a wild passerine population. Ecol. Evol. 12(2): e8582. https://doi.org/10.1002/ece3.8582
de Villemereuil P, Charmantier A., Arit D, Bize P, Brekke P, Brouwer L, Cockburn A, Côte SD, Dobson FS, Evans SR, Festa-Bianchet M, Gamelon M, Hamel S, Hegelbach J, Jerstad K, Kempenaers B, Kruuk LEB, Kumpula J, Kvalnes T, McAdam AG, McFarlane SE, Morrisey MB, Pärt T, Pemberton JM, Qvarnström A, Røostad O-W, Schroeder J, Senar JC, Sheldon BC, van de Pol M, Visser ME, Wheelwright NT, Tufto J, Chevin L-M. (2020) Fluctuating optimum and temporally variable selection in the wild. PNAS. 117(50), 31969–31978. https://doi.org/10.1073/pnas.2009003117
Westneat D, Bókony V, Burke T, Chastel O, Jensen H, Kvalnes T, Landvai A, Liker A, Mock D, Schroeder J, Schwagmeyer PL, Sorci G, Steward IRK. (2014) Multiple aspects of plasticity in clutch size vary among populations of a globally distributed songbird. J. Anim. Ecol. 83, 876–887.
Schroeder J, Piersma T, Groen N, Hooijmeijer J, Kentie R, van der Velde M, Lourenço PM, Schekkerman H, Both C (2012) Reproductive timing and investment in relation to spring warming and advancing agricultural schedules. J. Ornithol. 153, 327–336.
Lourenço P, Kentie R, Schroeder J, Groen NM, Hooijmeijer J, Piersma T (2011) Repeatable timing of northward departure, arrival and breeding in black-tailed godwits Limosa l. limosa, but a surprising absence of domino effects. J. Ornithol. 152, 1023–1032.
Schroeder J, Hinsch M, Mitesser O 2010. Correlations between sequential timing decisions not necessarily indicate strategic behavior. Am. Nat. 176, 835-837