Data from: The role of partial incubation and egg repositioning within the clutch in hatching asynchrony and subsequent effects on breeding success

The main mechanism to achieve hatching asynchrony (HA) for incubating birds is to start heating the eggs before clutch completion. This might be achieved through partial incubation and/or early incubation. Even in the absence of incubation behaviour during the laying phase, clutches still experience a certain degree of asynchrony. Recent studies have shown that eggs located in the centre of the nest receive more heat than peripheral ones during incubation. Since eggs receiving more heat would develop faster, we hypothesised that HA should be shorter in nests where eggs were moved homogeneously along the centre-periphery space during incubation compared to those nests where eggs repeatedly remained in the same locations, either centrally or peripherally. We explored the relative roles of egg repositioning and partial incubation in determining HA in wild birds by (1) removing eggs from 20 Great Tit Parus major nests on day of laying and replacing them with fake eggs to avoid partial incubation, and returning them when full incubation began; (2) monitoring twice a day the position of each individually marked egg relative to the clutch centre during incubation, and estimating the coefficient of variation of the distances (CVdistance); (3) determining HA in each nest. Preventing partial incubation reduced HA by 51% days in experimental nests. It also caused negative effects for the incubating females (lengthening the full incubation period) and positive effects for the brood (increasing fledging success). However, our hypothesis about the role of egg repositioning on HA was not supported: all the females moved the eggs with remarkable consistency, generally attaining a CVdistance around 33%, and it was not related to the HA experienced. We therefore conclude that partial incubation is an important factor regulating HA, and females compensate for the potential effects of differential heating by moving the eggs homogeneously within the clutch

The role of partial incubation and egg repositioning within the clutch in hatching asynchrony and subsequent effects on breeding success

The main mechanism to achieve hatching asynchrony (HA) for incubating birds is to start heating the eggs before clutch completion. This might be achieved through partial incubation and/or early incubation. Even in the absence of incubation behaviour during the laying phase, clutches still experience a certain degree of asynchrony. Recent studies have shown that eggs located in the centre of the nest receive more heat than peripheral ones during incubation. As eggs receiving more heat would develop faster, we hypothesized that HA should be shorter in nests where eggs were moved homogeneously along the centre–periphery space during incubation than in those nests where eggs repeatedly remained in the same locations, either centrally or peripherally. We explored the relative roles of egg repositioning and partial incubation in determining HA in wild birds by (1) removing eggs from 20 Great Tit Parus major nests on the day of laying and replacing them with fake eggs to avoid partial incubation, and returning them when full incubation began; (2) monitoring twice a day the position of each individually marked egg relative to the clutch centre during incubation, and estimating the coefficient of variation of the distances; and (3) determining HA in each nest. Preventing partial incubation reduced HA by 51% days in experimental nests. It also caused negative effects for the incubating females (lengthening the full incubation period) and positive effects for the brood (increasing fledging success). However, our hypothesis about the role of egg repositioning on HA was not supported: all the females moved the eggs with remarkable consistency, generally attaining a coefficient of variation of the distances around 33%, and it was not related to the HA experienced. We therefore conclude that partial incubation is an important factor regulating HA, and females compensate for the potential effects of differential heating by moving the eggs homogeneously within the clutch.This study was supported by project CGL2013-48001-C2-1-P (Spanish Ministry of Economy and Competitiveness, MINECO). D.D.-M. benefitted from an FPI grant (BES-2014-069191) provided by the MINECO, and S.R. from an FPU grant (AP2010-5723) provided by the Spanish Ministry of Education, Culture and Sports

Synthesis, characterisation and natural abundance Os-187 NMR spectroscopy of hydride bridged triosmium clusters with chiral diphosphine ligands

Treatment of [Os3(μ-H)2(CO)10] with the chiral diphosphines BINAP, tolBINAP [(R)-2,2′-bis(di-4-tolylphosphino)-1,1′-binaphthyl], DIOP [(4R,5R)-(−)-O-isopropenylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane] affords [Os3(μ-H)2(CO)8(μ-L)] (L = BINAP (1), tolBINAP (2), DIOP (4)) in high yield. The X-ray structures for 1, 2 and 4 are reported, and structural and spectroscopic comparisons are made between these clusters and [Os3(μ-H)2(CO)8(μ-L)] (L = dppm (5), dppe (6), dppp (7)) which were synthesised similarly. Compounds 5 to 7 were previously synthesised by hydrogenation of 1,2-[Os3(CO)10(μ-L)] but the route from [Os3(μ-H)2(CO)10] is preferable. The H-bridged Os⋯Os distances are similar in 1, 2 and 4 indicating that these species are formally unsaturated 46-electron clusters. The P⋯P distances vary from 4.24 to 4.30 Å in 1 and 2, respectively, to 4.53 Å in 4 and there are related changes in the angles associated with the ligand set around the H-bridged osmium atoms. Introduction of the diphosphine ligands completely suppresses the ability to add CO, to insert acetylene to form a μ-η1,η2-vinyl compound, and to exchange hydride ligands with styrene-d8, which are reactions characteristic of [Os3(μ-H)2(CO)10]. Clusters 2 and 5–7 were also used to examine the potential of natural abundance 187Os NMR spectroscopy through techniques based on inverse detection by HMQC, HSQC and HMBC spectroscopy

The structure and function of nests of Long-Tailed Tits Aegithalos caudatus

1. The aim of this study was to investigate the structure and thermoregulatory function of nests of the Long-Tailed Tit, Aegithalos caudatus. 2. The feather lining of Long-Tailed Tit nests represents a major portion (41%) of the total nest mass. 3. The mass of feathers varied among nests and declined through the breeding season, but there was no seasonal loss of nest insulation quality because of increasing ambient temperatures. 4. In an experiment to investigate the seasonal decline in the feather mass of nests, feathers were added to nests at an early stage of the lining phase of nest construction. Nest structure and insulating properties were then examined following nest completion. 5. The total mass of feathers in treatment and control nests did not differ significantly and there was no significant difference in their nest insulation quality. 6. Our results demonstrate that Long-Tailed Tits adjust their nest-building behaviour according to the nest's thermal environment. Moreover, nest structure appears to be adjusted to prevailing environmental conditions rather than being a function of feather availability or time constraints