Australian and African finches are easily bred in captivity. That is the reason why they are widely used in studies, especially in behavioral research. The Zebra Finch, Taeniopygia guttata, is very likely one of the most popular birds for scientific research. Some of the contributions Finches are making to science are shown below.

... This study tests whether zebra finches utilize photoperiod independently of other proximate cues, specifically food availability. Our data demonstrate that long days alone are not sufficient to drive reproductive development in this opportunistically breeding species. Rather, it appears that reproductive development is stimulated by exten-ded feeding times or increased food abundance during long days, and not by changes in day length per se / Perfito N, Kwong JM, Bentley GE, Hau M. Cue hierarchies and testicular develop-ment: Is food a more potent stimulus than day length in an opportunistic breeder (Taeniopygia g. guttata)? // Horm Behav. 2008 Apr;53(4):567-72.                                       

... Our results suggest that black-throated finches (Poephila cincta) diverged from long-tailed finches (P. acuticauda and P. hecki) across the Carpentarian Barrier in northeastern Australia around 0.6 million years ago (mya), and that P. acuticauda diverged from P. hecki across the Kimberley Plateau-Arnhem Land Barrier in northwestern Australia approximately 0.3 mya / Jennings WB, Edwards SV. Speciational history of Australian grass finches (Poephila) inferred from thirty gene trees // Evolution Int J Org Evolution. 2005 Sep;59(9): 2033-47.    

... We exposed male zebra finches (Taeniopygia guttata) to environmental stress by exposing them to two temperature regimes (6 and 26 degrees C) over a 4 week period. Simultaneously, half of the males in each temperature group were supplemen-ted with carotenoids, whereas the other half were not. The expression of a carotenoid-based sexual trait (bill colour) and the amount of circulating carotenoids were assessed before and at the end of the experiment. Carotenoid-supplemented males developed a redder bill, but the effect of supple-mentation was reduced under cold exposure. However, we found evidence that birds facing a cold stress were carotenoid limited, since supple-mented males developed redder bills than the non-supplemented ones /  Eraud C, Devevey G, Gaillard M, Prost J, Sorci G, Faivre B. Environ-mental stress affects the expres-sion of a carote-noid-based sexual trait in male zebra finches // J Exp Biol. 2007 Oct;210(Pt 20):3571-8.

... We raised male zebra finches to adulthood in a controlled environment, and were then exposed them to either a single unfamiliar female (simple social environment) or to 45 unfamiliar zebra finches of both sexes (complex social environ-ment). Their singing behavior was monitored in these new social environments. Birds which were exposed to a simple social environment sang significantly more than birds which were exposed to a complex social environment / Adar E, Lotem A, Barnea A.The effect of social environment on singing behavior in the zebra finch (Taeniopygia guttata) and its implication for neuronal recruitment // Behav Brain Res. 2008 Feb 11;187(1):178-84.                          

... We still know surprisingly little about whether individual females differ intrinsically in their prin-cipal readiness to copulate, and to what extent this readiness is affected by male attractiveness. To address this question I used captive zebra finches (Taeniopygia guttata) as a model system. Females showing a high readiness to copulate when cour-ted by a male for the first time in life were much more likely to engage in extra-pair copulations later in life than others. Male attractiveness, as measured in choice tests, was a useful predictor of whether females engaged in extra-pair copulations with these males, but, surprisingly, the attractive-ness of a female's social partner had no effect on her fidelity. However, it remained unclear what made some males more attractive than others. Contrary to a widespread but rarely tested hypothesis, females did not preferentially copulate with males having a redder beak or singing at a higher rate / Forstmeier W. Do individual females differ intrinsically in their propensity to engage in extra-pair copulations? // PLoS ONE. 2007 Sep 26;2(9):e952.

... We genotyped 1000 zebra finches from 18 captive and two wild populations at 10 highly variable microsatellite loci. We found that all captive populations have lost some of the genetic variability present in the wild, but there is no evidence that they have gone through a severe bottleneck / Forstmeier W, Segelbacher G, Mueller JC, Kempenaers B. Genetic variation and differentiation in captive and wild zebra finches (Taeniopygia guttata) // Mol Ecol. 2007 Oct; 16(19):4039-50.              

... It is shown through a controlled experimental manipulation that zebra finches (Taeniopygia guttata) allowed to remain with their partners to breed again are faster to initiate a clutch (by approx. 3 days) than birds separated from their mates that have to re-pair / Adkins-Regan E, Tomaszycki M. Monogamy on the fast track // Biol Lett. 2007 Dec 22;3(6):617-9.

... The mate choice tests with adult zebra finches (Taeniopygia guttata) indicate that nutritional condi-tions during the period of song learning, brain and gonad development, and moult into adult plumage have persisting effects on male attractiveness / Naguib M, Nemitz A. Living with the past: nutri-tional stress in juvenile males has immediate effects on their plumage ornaments and on adult attractive-ness in zebra finches // PLoS ONE. 2007 Sep 19; 2(9): e901. 

... In Gouldian finches(Erythrura gouldiae), females paired with genetically incompatible males of alternative color morphs overproduce sons, presumably to reduce investment in inviable daughters. We also observed a reduced overall investment in clutch size, egg size, and care to offspring resulting from incompatible matings. Within-female experimental pairings demonstrate that female birds have the ability to adaptively adjust the sex of their eggs and allocate resources on the basis of partner quality. Female Gouldian finches thus make cumulative strategic allocation decisions to minimize the costs of poor-quality pairings when faced with a genetically incompatible partner /  Pryke SR, Griffith SC. Genetic incompatibility drives sex allocation and maternal investment in a polymorphic finch // Science. 2009 Mar 20;323(5921):1605-7.

... By experimentally infecting the feathers and cloaca of captive zebra finches (Taeniopygia guttata), with the bacterium Bacillus licheniformis PWD1 (BL), we examined the self-contamination and horizontal transmission of birds sharing the same environment. We also examined whether sexual transmission of bacteria is gender biased. Our results show that bacteria placed on the plu-mage of the birds lead to self and allo-infections of the bird guts, possibly through preening beha-viours and bacterial ingestion. Furthermore, we found that sexual transmission of the bacteria was asymmetrical, being higher when males are the transmitting sex / Kulkarni S, Heeb P. // Social and sexual behaviours aid transmission of bacteria in birds // Behav Processes. 2007 Jan 10;74(1):88-92. 

... Choice of genetically unrelated mates is widely documented, yet it is not known how self-referen-tial mate choice can co-occur with commonly observed directional selection on sexual displays. Across 10 breeding seasons in a wild bird popu-lation, we found strong fitness benefits of matings between genetically unrelated partners and show that self-referential choice of genetically unrelated mates alternates with sexual selection on elaborate plumage. Seasonal cycles of diminishing variation in ornamentation, caused by early pairing of the most elaborated males, and influx of increasingly genetically unrelated available mates caused by female-biased dispersal, lead to temporal fluctua-tions in the target of mate choice and enabled coexistence of directional selection for ornament elaboration with adaptive pairing of genetically unrelated partners / Oh KP, Badyaev AV. Adaptive genetic complementarity in mate choice coexists with selection for elaborate sexual traits // Proc Biol Sci. 2006 Aug 7; 273(1596):1913-9 

... For many bird embryos, periodic cooling occurs when the incubating adult leaves the nest to forage, but the effects of periodic cooling on embryo growth, yolk use, and metabolism are poorly known. To address this question, we conducted incubation experiments on eggs of zebra finches (Taeniopygia guttata) that were frequently cooled and then rewarmed or were allowed to develop at a constant temperature. After 12 d of incubation, embryo mass and yolk reserves were less in eggs that experienced periodic cooling than in controls incubated constantly at 37.5 degrees Celsius. Embryos that regularly cooled to 20 degrees Celsius had higher mass-specific metabolic rates than embryos incubated constantly at 37.5 degrees Celsius. Periodic cooling delayed development and increased metabolic costs, reducing the efficiency with which egg nutrients were converted into embryo tissue / Olson CR, Vleck CM, Vleck D. Periodic cooling of bird eggs reduces embryonic growth efficiency // Physiol Biochem Zool. 2006 Sep-Oct;79(5):927-36. 

  ... Zebra finches (Taeniopygia guttata) reared in small or large experimental broods became high- or low-quality adults, respectively. Only high-quality females preferred high-quality males' mate-advertising songs, while all low-quality females preferred low-quality males' song. Females produced larger eggs when mated with high-quality males, regardless of their own quality, indicating consensus regarding male quality despite the expression of different choices / Holveck MJ, Riebel K. Low-quality females prefer low-quality males when choosing a mate // Proc Biol Sci. 2010 Jan 7;277(1678):153-60.