Patrilineal fertility decline along the Croatian frontier: 1720 - 1850

Eugene A. Hammel and Joshua R. Goldstein
Department of Demography
University of California, Berkeley
2232 Piedmont Avenue
Berkeley, CA
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Some preliminary findings


In 1976 Richard Easterlin proposed a scenario for the occurrence of high fertility on the edge of a rolling frontier and its decline behind that frontier as the frontier rolled forward. The basic idea is that landowning farm parents, concerned to endow their children, feel little constraint on child production when land is abundant at the edge of the frontier, but come to feel that constraint as the frontier rolls beyond them, so that they control their fertility as local population increases and the effective availability of land for endowment declines. Similarly, in 1931 an epidemiologist named Pirc published an analysis of the decline of fertility in Slavonia (the region between Belgrade and Zagreb) between about 1800 and 1930. In that analysis he established that long-settled families had lower fertility (in the cross-section) than did immigrant families. Pirc's results are in accord with Easterlin's theory and his observations about the North American frontier. We would expect from these results that fertility would decline within inheriting family lines in general and specifically in Slavonia.

We propose to examine the Easterlin-Pirc hypothesis by analyzing family reconstitution records (thus, longitudinal data) from a region of Slavonia just west of where Pirc worked, but c. 1720-1850. In 1683-91 this region was denuded of 80\% of its population as the Austrians ejected the Ottomans from it. From 1691-1750 new migrants flooded into the area, where land was abundant. By 1821 land shortage was a state concern. We detect signals of aggregate fertility limitation and decline starting c. 1780. This is as early as in France but occurred not in a (then) modernizing economy, rather in one that was reverting to medieval feudal institutions. Studies of short term fluctuations 1760-1860 also show negative effects of increased prices or harvest shortages on fertility. Ethnographic sources indicate that the mechanism of limitation was abortion.

Of course, aggregate fertility decline can be affected by the differential fertility of in-migrants or out-migrants. For example, fertility decline in families could be entirely obscured in the aggregate by continuing inflows of high fertility migrants. In this paper we examine whether fertility declines {\em in family lines} as the Easterlin and Pirc hypotheses would suggest.

Land inheritance in this culture at this time was strictly patrilineal and agnatic; females did not inherit or transmit land. Thus land shortage would have been felt in the patrilineage.

We expect that, if the Easterlin-Pirc hypotheses are correct, identifiable patrilineages will show declining fertility over time, net of any period influences such as wars or epidemics that might have affected family formation. We may also expect that succeeding patrilineages founded by new immigrants will exhibit a decline in initial, entrance level, fertility. These two hypotheses are motivated by the expectation that (1) a resident patrilineage will decrease its fertility as its land resources become more constrained, and (2) incoming migrants will also reduce their fertility somewhat as they perceive the land constraint.

We explore three methods of analysis. The first simply identifies chains of fathers in baptismal records and counts the numbers of men at each generation in such a chain. Each such set have a common father and are thus brothers. The intergenerational ratios are successive male NRRs, net of linkage failures. This method will pick up men who are fathers even if their marriage records have not been linked, but it will include some men who are in-migrants and married prior to arrival in the catchment area.

The second method is similar but uses only males with known marriage records. None of these men are in-migrants. Those with well-defined dates of the end of marriage are not out-migrants, but some of those for whom the ending date of the marriage is unknown may be out-migrants.

The third method is similar to the second but utilizes the DRAT measure of individual level fertility (Boulier and Rosenzweig, 1978) for the first wives of men in patrilineal chains. This method focuses on the family units in which we would expect fertility planning to be most apparent.

Some preliminary findings

We have reconstructed 1,145 patrilineal chains with a length of at least three generations. An early analysis of these chains suggests a strong fertility decline within lineages, with the first generation of settlers having much higher fertility than their sons. The average number of sons per member in the first generation is 3.64, while the average number of sons per member in the second generation falls to 1.52. The decline is all the more striking in that it is concentrated among families that had many sons in the first generation. One can see the strong inverse relationship between male offspring of the first generation and male offspring of the second generation in figure (not shown). The frequencies are given in table 1.

TABLE 1: Relative number of recorded sons fathered by first and second generations
Sons fathered by
1st generation
Average number of sons
fathered by 2nd generation
Number of patrilines
1 3.67 163
2 1.98 200
3 1.31 214
4 0.97 219
5 0.80 145
6 0.73 116
7 0.62 52
8 0.58 24
9 0.38 10
10 0.80 1
11 0.64 1
The above comparison of the number of males present in each generation reflects the combined effects of fertility-decline and outmigration. To be linked to a patriline, a child must be born or marry within the region. Thus, while the apparent fertility decline may indeed reflect smaller numbers of children ever-born, it may also reflect the tendency of males with few prospects of land-inheritance to out-migrate either before marriage or before all their children are born. Subsequent methods will address the relative importance of outmigration and fertility control by restricting the analysis only to individuals who died or whose marriages ended within the region.

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