Future studies needed

Because human activities often fragment songbird habitat, resulting in isolated habitat patches with smaller population sizes (Vitousek 1994), there are plenty of opportunities to test the effects of isolation and population size on song learning in future observational studies. It is also possible to manipulate a young bird's social environment in field and laboratory populations during the later stages of song learning, and then monitor closely the subject's song development as it proceeds....

Excavation history nest tree and cavity characteristics

In terms of the flow of nest-cavity resources among the small cavity-nesters, mountain chickadees depended primarily on cavities excavated by red-naped sapsucker (40 of 163 cavities where cavity origin was determined), red-breasted nuthatch (23 ), downy woodpecker (17 ), and natural holes (11 Table 8.1). Despite the presence of both chickadee species nesting on 21 of the 26 sites between 1995 and 2004, only two of 163 nesting attempts by mountain chickadees were in holes excavated by...

Hybridization among Eurasian Parids

Observations of mixed breeding pairs, or of pheno-typically intermediate individuals, have provided evidence for hybridization among numerous European and Asian Parids. Rare hybridization, implied by anecdotal reports of mixed pairs or intermediate specimens, has involved willow X marsh tit willow X coal tit willow X crested tit coal X crested tit blue X great tit marsh X great tit great X coal tit and willow X varied tit (reviewed by Harrap and Quinn 1995 Curry 2005 McCarthy 2006)....

Neurogenesis in the hippocampus of the adult blackcapped chickadee

A number of studies have addressed the role of adult neurogenesis in the processing of spatial information in the hippocampus. The first work to examine neurogenesis in the black-capped chickadee was that of Barnea and Nottebohm (1994) Extensive research had previously described adult neurogen-esis in the oscine song control system, much of this work conducted by Nottebohm and his colleagues (Nottebohm 2002), leading to a detailed picture of the location and nature of neural progenitor cells,...

Description of study system

I first explain what is known about song learning in black-capped chickadees and then describe my study system. Laboratory audio-tutoring experiments demonstrate that chickadees exposed to appropriate conspecific song are more likely to develop whistled song than chickadees without such exposure (Shackleton and Ratcliffe 1993 Kroodsma et al. 1995 K. A. Otter unpublished data). Chickadees in all previous audio-tutoring experiments failed to imitate song precisely and accurately, suggesting that...

Song patterns beyond and within hybrid zone

Song patterns were consistent with the assumption that sites other than NF were outside of, or at the extreme edge of, the hybrid zone. Among songs sampled in 2000-2001 from GM and other Carolina localities, all songs analyzed matched the typical see-bee-see-bay Carolina chickadee song type (n 51 songs), except we recorded one bird in southern Montgomery Co., Pennsylvania, that gave only three-note songs (see-bay-see n 13) representing the Song Variant category of Smith (1972). All songs in...

Vocal communication

Parids are among the best-studied avian family, globally, with respect to vocal communication. Although not necessarily elaborate songsters, Parids have extremely diversified vocalizations which have formed rich fodder for entire research careers. North American chickadees and titmice (and their Eurasian Poecile counterparts) also have vocal attributes that make this family unusual, as they do not follow the commonly held definition that distinguishes songs (structurally complex, learned...

The hippocampus

Having discovered the capacity of food-storing chickadees and tits to relocate cache sites and the cognitive means by which they do this, researchers turned to the neural mechanisms behind the birds' Figure 2.3 The hippocampus of the cynomolgus monkey (Macaca fascicularis), rat, and pigeon. Two interfolded structures, the dentate gyrus (DG) and Ammon's horn, or cornu ammonis (CA), make up the mammalian hippocampus. Scale bars equal 2 mm. APH area parahippocampalis CA1, CA3 cells fields of the...

Song patterns in the Pennsylvania contact zone

A striking finding in our study was the retention of black-capped chickadee songs at NF, where essentially all resident adults are now hybrids (and where some may be genetically pure Carolina chickadees). Even those males with the ability to sing at least one Carolina song type continue to produce black-capped songs as well. That existence of bilingual chickadees may indicate interbreeding has been long assumed, with some even suggesting that bilingual males in zones of overlap might gain a...

Food storing in the wild

Food storing has a strong seasonal component in Parids, beginning in autumn and continuing through the winter into early spring (Brodin 1994 Haftorn 1956 Ludescher 1980 Nakamura and ater aemodius melanolophus ater ater monticolus holsti spilonotus xanthogenys afer albiventris Parus humilis Parus caeruleus Parus cyanus Figure 2.1 The distribution of food-storing in the Paridae, shown on a phylogeny proposed by Gill etal. (2005). Dark shaded boxes show species known to store, light shaded boxes...

Interactive playback experiment II

We tape-recorded subjects by the mirror-only stimulation so that their complete repertoires were known. We tested six birds in a setup like that used in Interactive Playback Experiment I. The microphone led to a sound spectrograph operating in real time, which allowed experimenters to monitor the vocal output of the subject. Another experimenter operated a computer, with icons on the screen representing the gargle types in the repertoire of the subject (Bradbury and Vehrencamp 1994). The gargle...

The feebee song Variation on a twonote theme

In contrast to birds where each individual possesses a repertoire of song types, male black-capped chickadees typically have just one song type. However, male chickadees vary their songs by transposing the two-note fee-bee up and down a frequency continuum (Fig. 14.1b Horn et al. 1992). Originally, black-capped chickadees were understood to have two song variants a normal song at one frequency and a shifted song at another (Ratcliffe and Weisman 1985 Hill and Lein 1987 Chapter 10). Today we...

Seasonal neural plasticity

In addition to seasonal changes in peripheral physiology and behavior, birds also exhibit remarkable seasonal brain plasticity (Tramontin and Brenowitz 2000). There is good evidence that the entire brain may exhibit seasonal morphological changes (Smulders 2002). Most research on birds, however, has focused on seasonal plasticity in three neural systems the gonadotropin-releasing hormone (GnRH) system, the song-control system, and the hippocampus. GnRH is a hypothalamic neuropeptide that...

Susan M Smith

An amazing amount of new information has been discovered since I published my first book on chickadees (Smith 1991). Among the most fundamental of these advances is the work of Frank Gill and his colleagues on the genetic relationships within the Family Paridae. Working with mitochondrial DNA, in particular the mitochondrial cytochrome-B gene, Gill et al. (2005) have arrived at an overview of the degree of relatedness among the members of this avian family. Evidently there have been two...

Interspecific differences

Almost all food-caching birds live in environments with pronounced differences between seasons in accessibility of food. As a result, the benefits of strong spatial memory and food caching might typically be higher during the winter when environmental conditions are most energetically demanding. Also, some species experience more severe environmental conditions than others. Consequently, the advantages of food caching should be much higher for species living in more energetically demanding...

Population growth models

We calculated mountain chickadee population growth rates (r) by taking the natural log of the average number of individuals per study site at time (year), t+1 divided by the average number of detections per site at time t (adding a correction factor of 0.5 to each population count because census data typically contain zeroes, and the addition of a small constant to every estimate of population density is needed to avoid division by zeroes in calculating growth rates-Framstad et al. 1997). We...

Nest cavities and male singing behavior

Communication network theory suggests that females should position themselves in order to maximize assessment of the males around them (Otter and Ratcliffe 2005). The nesting behavior of black-capped chickadees provides support for this theory. Black-capped chickadees routinely construct their nests closer to the edges of their territories than would be expected by chance (Ramsay et al. 1999). Nests typically fall within 20 m of territory edges, despite the large size of chickadee territories...

Female eavesdropping in blackcapped chickadees

Using a modified version of Otter et al. (1999) interactive playback study, Mennill et al. (2002, 2003) engaged male chickadees in countersinging contests with a simulated intruder to test whether female black-capped chickadees eavesdrop on male-male song interactions. The experiment involved playback to groups of four birds two pairs of breeding partners in neighboring territories, where the males had been flock-mates during the previous winter, one high-ranking and one low-ranking. Playback...

Syntactical information

There are at least three ways that we can begin to understand the meaning of the chick-a-dee call from the perspective of syntactical information. The first, pioneered by Hailman et al. (1985), is a structural analysis of syntax per se to determine the hypothetical information that may reside in a signaling system. The second is a natural-history approach, documenting calls produced in natural settings and what behavioral or other contextual correlates exist (e.g. Smith 1972). The third is an...