Food-chain chemistry, reproductive success, and foraging behaviour of songbirds in acidified maple forests of central Ontario

Abstract

We examined the breeding success of two insectivorous bird species, the resident black-capped chickadee (Parus atricapillus) and the Neotropical migrant chestnut-sided warbler (Dendroica pensylvanica), in relation to food-chain chemistry at a healthy and a declining forest site in central Ontario, Canada. The health of sugar maples (Acer saccharum) was poorer and the pH of both soil and throughfall was lower at the declining site than at the healthy site. The calcium and magnesium concentrations and the ca1cium:aluminum ratio in the soil were also lower at the declining site than at the healthy site. The calcium, magnesium, and phosphorus concentrations and the ca1cium:aluminum ratio in sugar maple foliage were lower at the declining site than at the healthy site, indicating extensive acid leaching of the soil and foliage at the declining site. Caterpillars (Geometridae) at the declining site had a lower calcium concentration and beetles had a lower magnesium concentration than these groups at the healthy site. The ca1cium:aluminum ratios in the tissues of insects in both groups were lower at the declining site than at the healthy site, paralleling the foliar and soil chemical differences. There were, however, no differences in clutch or brood sizes, or percent hatch, for either bird species between the healthy and declining sites. Chickadees consistently foraged lower in the canopy at the declining site, a possible compensatory behaviourial response to canopy dieback and (or) lower food quality in the upper canopy.RCsumC : Nous avons CtudiC le succks de la reproduction chez deux espkces d'oiseaux insectivores, la MCsange 8 tCte noire (Parus atricapillus), une espkce rCsidante, et la Paruline h flancs marrons (Dendroica pensylvanica), une espkce migratrice NCotropicale, en rapport avec la chimie de la chaine alimentaire dans des habitats forestiers sains et en dCclin du centre de I'Ontario, Canada. Dans la forCt en dCclin, la santC des Crables 8 sucre (Acer saccharum) Ctait moins bonne et le pH du sol et des pluies non intercepties Ctait plus faible que dans la forCt saine. Dans le sol de la forCt en dCclin, les concentrations de calcium, de magnCsium et le rapport calcium : aluminium Ctaient plus faibles qu'au site sain. Les concentrations de calcium, de magnCsium, de phosphore et de rapport calcium : aluminium dans le feuillage des Crables 8 sucre Ctaient Cgalement plus faibles que dans la forCt saine, ce qui indique un important lessivage 8 l'acide du sol et du feuillage dans la forCt en dCclin. Les chenilles des Geometridae contenaient moins de calcium et les colCoptkres, moins de magnksium, au site affect6 qu'au site sain. Les rapports calcium : aluminium dans les tissus des insectes des deux groupes Ctaient plus faibles au site affect6 que dans la for& saine, suivant les mCmes tendances que les diffkrences chimiques dans le feuillage et dans le sol. Par ailleurs, il n'y avait pas de diffkrence dans le nombre d'oeufs, le nombre d'oisillons ou le nombre d'oisillons parvenus 8 1'Cclosion entre les deux sites. ...

Adverse effects of acid rain on the distribution of the Wood Thrush Hylocichla mustelina in North America

“…Although the proximate cause of decreases in the probability of breeding is as yet unclear, it seems unlikely to be eggshell abnormalities, as the studies that address this issue in North American terrestrial bird species have not shown eggshell defects severe enough to cause their failure (3,(37)(38)(39)(40)(41). Decreased probability of breeding may also be the result of demographic changes less drastic than complete reproductive failure, although most studies (37,(40)(41)(42) have not demonstrated such changes (but see also ref.…”

“…Decreased probability of breeding may also be the result of demographic changes less drastic than complete reproductive failure, although most studies (37,(40)(41)(42) have not demonstrated such changes (but see also ref. 38).…”

The Bioavailability and Toxicity of Aluminum in Aquatic Environments

“…For example, dippers (Cinclus cinclus) near acidic streams showed blood chemistry reflecting calcium scarcity (Tyler and Ormerod, 1992); insufficient dietary Ca can affect eggshell production in birds. However, birds may alter their foraging behavior to compensate for lower calcium food sources (Mahony et al, 1997). St.…”

Dietary calcium limits size and growth of nestling tree swallows Tachycineta bicolor in a non‐acidified landscape

“…Nestling tree swallows that received extra dietary calcium during the brood‐rearing period had enhanced rates of growth for both mass and ninth primary feathers, and were larger at age 16 days than were control nestlings. While other studies have found that supplementing calcium in the diets of insectivorous birds has beneficial consequences for reproductive success (Graveland et al 1994, Graveland 1996, Graveland and van der Wal 1996, Graveland and Drent 1997, Weimer and Schmidt 1998, Mänd et al 2000, Mänd and Tilgar 2003; but see Mahony et al 1997, Ramsay and Houston 1999), the vast majority of research has been conducted in areas suffering from acid deposition or in areas where calcium is not abundant. In contrast, Tilgar et al (2002) have recently shown that great tits were limited by calcium in an area of Estonia where acid deposition has not impacted the ecosystem, and so calcium is relatively abundant.…”

“…In recent years, the deposition of acidic precipitation in various ecosystems has illustrated the importance of calcium limitation in the reproduction of birds. Acid deposition, especially in base‐poor areas, causes a reduction in available soil calcium (Ramsay and Houston 1999; but see Mahony et al 1997, Ormerod and Rundle 1998), and an associated decline in the abundance of calcium‐rich prey items, such as snails (Graveland et al 1994, Graveland and van der Wal 1996), that insectivorous and granivorous birds need to meet their calcium demands. In areas of Europe and North America where such changes have occurred, research has shown that birds perform poorly, both in terms of producing eggs and the growth of their offspring (Drent and Woldendorp 1989), and in some cases, these effects can be reversed by providing supplemental calcium (Graveland et al 1994, Graveland and Drent 1997).…”