104 THE WILSON BULLETIN • Vol. 113, No. 1, March 2001

Wilson Bull., 113(1), 2001, pp. 104±108

Aspects of the Breeding Biology of the Crested Gallito

Eduardo T. Mezquida1,2

ABSTRACT.ÐI studied the breeding biology of the Crested Gallito (Rhinocrypta lanceolata) and Crested Gallito (Rhinocrypta lanceolata) in the Re- the Sandy Gallito (Teledromas fuscus; Naros- Ä serve of NacunÄaÂn (western ) from September ky and Yzurieta 1987). The Crested Gallito is 1995 to January 1999. The laying period extended from mid-September to late January, a month longer a relatively large with a bushy crest than previous reports from Argentina. The closed nest (FjeldsaÇ and Krabbe 1990, Ridgely and Tudor was globular with a side entrance and was made pri- 1994) and is resident in the Reserve of NÄ a- marily of grasses. In NÄ acunÄaÂn, this preferred cunÄaÂn (Mendoza Province, Argentina; Marone to nest in atamisque (Capparis atamisquea). Atam- 1992). The breeding biology of this species is isques selected for nesting were 1.6±3.5 m in height, poorly known and only limited characteristics and nests were 1.0±2.1 m above the ground. Mean clutch size (2.2 eggs) did not show a year or a seasonal of the nests and eggs have been described variation. Mean egg size and mass were less than those (Fraga and Narosky 1985). Other important reported previously. The incubation period lasted 16± life history traits, such as the duration of in- 17 d and the nestling period 14±15 d. Eggs hatched cubation and nestling stages, have not been asynchronously. No cases of brood parasitism by published previously. This note presents data (Molothrus bonariensis) were ob- about breeding biology parameters of the served. Received 31 July 2000, accepted 3 February Crested Gallito, including phenology of clutch 2001. initiation, nest, nest sites, eggs, laying inter- val, clutch size, length of incubation and nes- tling periods, and development of nestlings, in The Family Rhinocryptidae includes 35 an arid area of Argentina. recognized species found primarily in south- ern South America (FjeldsaÇ and Krabbe METHODS 1990). These are almost entirely insec- I studied the Crested Gallito in the Reserve of NÄ a- tivorous, predominantly terrestrial, and have cunÄaÂn (34Њ 03Ј S, 67Њ 54Ј W; 12,282 ha), Mendoza secretive habits (Goodall et al. 1957, Ridgely Province, Argentina, from 1995±1999 during the and Tudor 1994). Most nest in holes, crevices, breeding seasons (September through February). The reserve (mean elevation ϭ 540 m) is in the central and burrows, but some species (of the genera portion of the Monte Desert Biome, a narrow latitu- Eugralla and Rhinocrypta) build closed nests dinal strip in western Argentina, at the foot of the An- in trees and shrubs (Fraga and Narosky 1985). des. The predominant habitat in the reserve is an open Two species of Rhinocryptidae inhabit the ¯exuosa woodland with abundant shrub plains of Mendoza Province, Argentina: the (mainly Larrea divaricata, Capparis atamisquea, Ly- cium spp.) and grass cover (e.g., genera Pappophorum, Trichloris, Sporobolus, Digitaria). NÄ acunÄaÂn's climate 1 Ecodes, UF&EV, IADIZA, Casilla de Correo 507, is dry and temperate with cold winters. Mean annual 5500 Mendoza, Argentina. rainfall is 331 mm, although it is highly variable from 2 Current address: P. Alameda de Osuna 74 1 C, year to year, with most (78%) precipitation occurring 28042 Madrid, Spain; E-mail: ricardo.mezquida@adi. in spring and summer (October through March; Ma- uam.es rone 1992, Mezquida 2000). SHORT COMMUNICATIONS 105

FIG. 1. Initiation of egg laying by the Crested Gallito, NÄ acunÄaÂn, Argentina, during four breeding seasons (1995±1999).

I began searching for nests in late September. I mea- tain the area covered by each species. Mean crown sured nest dimensions (external and internal diameter area of the species used by Crested Gallitos for from the entrance to the back, external height, and en- nesting was calculated from a random sample. I estab- trance diameter) for some nests, although external di- lished random transects and chose the closest plant at ameter and external height were recorded for only a 25-m intervals. For each plant I measured the maxi- small sample of nests. To characterize nest sites I re- mum diameter of the crown and its perpendicular to corded plant species, plant height, crown diameter of calculate the area of the ellipse formed by both di- the plant, height of the nest's entrance above ground, ameters. Sample size was Ͼ100 for all species, distance from nest's entrance to the top of the plant except Prosopis ¯exuosa where only 25 plants were directly above the nest, a periphery index (visually cal- measured. culated as the ratio of trunk to nest distance divided Frequency of nest placement among available plants by the canopy radius at nest height; Lazo and Ana- was compared using chi-square analysis. To analyze if baloÂn 1991), and number and diameter of branches nest height differed among nesting plants I used uni- supporting the nest. I visited nests every 1±3 d to mon- variate ANOVA. I compared clutch size among years itor status until failure or ¯edging. I numbered each and within the breeding season with Kruskal-Wallis egg with waterproof ink and measured its maximum and Mann-Whitney nonparametric tests. length and breadth to the nearest 0.1 mm. Egg and nestling mass were measured to the nearest 0.1 g. RESULTS Clutch initiation date was calculated either by direct observation or by extrapolation from known hatching I located 60 Crested Gallito nests during the or ¯edging dates. four breeding seasons. In 18 of these nests I compared the selection of plant species used for breeding activity was not observed, but I mea- nesting with the frequency distribution of the various sured characteristics of the nest site. The lay- species in the habitat to determine if nest plants were used in proportion to their availability. To estimate the ing period spanned from mid-September to density of each plant species I calculated the area cov- late January (Fig. 1). The earliest date of ered by each species on 60 random circular plots (10- clutch initiation was 15 September (in 1997) m radius) and divided it by the mean crown area of and the latest was 2 October (in 1998). The each plant species. I located 60 random plots and de- date of the last egg of the last nest found in termined percent cover of the various plant species us- NÄ acunÄaÂn was 31 January (range: 22 Novem- ing radial transects. Radial transects consisted of two perpendicular 20-m lines, with one line oriented north ber±31 January, during four breeding sea- and south. I selected 40 random points, with a mini- sons). mum distance 10 cm between consecutive points, The closed nest was globular with a side along each transect. The total number of points mea- entrance (mean external diameter Ϯ SE: 17.5 sured at each plot was 80. At each sampling point, I Ϯ 1.3 cm, n ϭ 5; internal diameter: 12.0 Ϯ inserted a thin aluminum rod vertically into the vege- 0.2 cm, n ϭ 39; external height: 14.8 Ϯ 0.5 tation and recorded the species of plant that touched cm, n 4; and entrance diameter: 6.9 0.2 the rod. Horizontal cover of each species was calcu- ϭ Ϯ lated as the number of points with hits of that plant cm, n ϭ 34). Nests were mainly leaves and divided by 80. These values were multiplied by the tillers of grasses of the genera Sporobolus, area of the circle formed by the radial transects to ob- Pappophorum, and Setaria, with some sticks 106 THE WILSON BULLETIN • Vol. 113, No. 1, March 2001

TABLE 1. Crested Gallito nest site characteristics, NÄ acunÄaÂn, Argentina, 1995±1999. Values are means Ϯ SE (n).

Plant species

Characteristics Prosopis ¯exuosa decorticans Capparis atamisquea Plant height (m) 5.5 Ϯ 0.3 (4) 3.2 Ϯ 0.2 (6) 2.3 Ϯ 0.1 (42) Crown diameter (m) Ð 2.4 Ϯ 0.4 (6) 3.4 Ϯ 0.1 (37) Nest height (m) 1.8 Ϯ 0.3 (4) 1.7 Ϯ 0.2 (7) 1.4 Ϯ 0.0 (43) Nest to canopy distance (m) 3.0 Ϯ 0.3 (3) 1.0 Ϯ 0.2 (6) 0.6 Ϯ 0.0 (37) Periphery index 0.5 Ϯ 0.2 (3) 0.4 Ϯ 0.1 (6) 0.5 Ϯ 0.0 (42) Number of branches supporting the nest Ð 4.5 Ϯ 0.5 (2) 5.1 Ϯ 0.2 (17) Diameter of branches supporting the nest (nm) 15.0 Ϯ 5.0 (2) 16.2 Ϯ 5.9 (9) 12.2 Ϯ 1.7 (77) of small shrubs (e.g., Lycium spp.) or trees in 1996; 2.3 Ϯ 0.1, n ϭ 12 in 1997; and 2.0

(e.g., chanÄar, Geoffroea decorticans), and thin Ϯ 0.3, n ϭ 6 in 1998; Kruskal-Wallis test, H3 vegetal ®bers and petioles of Prosopis ¯exu- ϭ 1.3, P Ͼ 0.7). Within the breeding season, osa towards the inner part. The inner part of the size of clutches initiated before the mean the nest was lined with hair, wool, or the cot- laying date (2.0 Ϯ 0.1, n ϭ 24) did not differ ton-like appendices of Digitaria californica signi®cantly from those initiated after the seeds. mean laying date (2.4 Ϯ 0.1, n ϭ 13; Mann- Crested Gallito nests (n ϭ 60) were built in Whitney U-test, U ϭ 105.0, P Ͼ 0.05). Thus, several plant species: Capparis atamisquea clutch size remained relatively constant (75.0%), Geoffroea decorticans (13.3%), Pro- throughout the breeding season as well as sopis ¯exuosa (6.7%), Condalia microphylla among years. The incubation period was 16± (1.7%), Bulnesia retama (1.7%), and Atriplex 17 d (16.8 Ϯ 0.2 d, n ϭ 5). Eggs hatched lampa (1.7%). Estimated frequency (from ran- asynchronously, with the last egg laid hatch- dom samples) of available plants in the habitat ing a day later than the ®rst one. was C. atamisquea (5.9%), G. decorticans At hatching (day 0), nestlings showed gray (43.7%), P. ¯exuosa (7.2%), C. microphylla down in the capital, spinal, humeral, alar, and (9.6%), B. retama (0.0%), and A. lampa crural feather tracts. The bill was light gray, (33.6%). Use of these plant species for nest ¯anges pale yellow, and the inside of the gape support was not proportional to their avail- yellow, skin reddish pink, and legs grayish 2 ability (␹ 5 ϭ 866.5, P Ͻ 0.001). Crested Gal- pink. Pin feathers began to emerge at 2±3 d litos clearly preferred atamisque for nesting. in alar and caudal feather tracts; all other On average, Crested Gallitos placed their feather tracts emerged on days 3±4. The un- nests 1.5 Ϯ 0.0m(n ϭ 57 nests) above the sheathing of pin feathers in all feather tracts ground and in a central position within the occurred at 6±8 d. The eyes began to open on plant (mean periphery index 0.5 Ϯ 0.0, n ϭ days 4±5, and skin, bill, and leg color became 51). Nest site characteristics varied in the darker after days 3±4. Mass increase of nes- three most commonly used plants (Table 1), tlings was gradual (Fig. 2). Because of asyn- e.g., nest height in atamisque was lower than chronous hatching, the older chicks were usu- in the two tree species Prosopis ¯exuosa and ally larger, and these size differences persisted Geoffroea decorticans; ANOVA, F2,51 ϭ 3.5, until ¯edging. Average length of the nestling P Ͻ 0.05. period was 14.2 Ϯ 0.2 days (range ϭ 14±15 Eggs of the Crested Gallito were ovoid d, n ϭ 5). (mean length and breadth: 27.7 Ϯ 0.1 ϫ 20.8 Ϯ 0.1 mm, n ϭ 71), white in color, weighed DISCUSSION 6.4 Ϯ 0.1g(n ϭ 56), and were laid on alter- nate days. Mean clutch size was 2.2 Ϯ 0.1 Crested Gallitos are permanent residents in eggs (range ϭ 1±3, n ϭ 40) with 2 eggs the NÄ acunÄaÂn (Marone 1992). They usually build most common (80%) clutch size. In NÄ acunÄaÂn, new nests every nesting season, although I mean clutch size did not differ among years have observed sporadic use of the same nest (2.2 Ϯ 0.2, n ϭ 5 in 1995; 2.1 Ϯ 0.1, n ϭ 16 in two consecutive breeding seasons and with- SHORT COMMUNICATIONS 107

FIG. 2. Growth of Crested Gallito nestlings, NÄ acunÄaÂn, Argentina, during four breeding seasons (1995±1999). Values are mean Ϯ SD (number of nestlings, number of nests). in a breeding season after a successful at- foliage shrubs (e.g., Raphithamnus cyanocar- tempt. pus) in southern Chile (Goodall et al. 1957). The laying period of the Crested Gallito In NÄ acunÄaÂn, the preference of Crested Gal- was one month longer than other reports from litos for atamisque for nest support, however, Argentina (Wetmore 1926, Smyth 1928, Per- was not associated with higher probability of eyra 1951, Fraga and Narosky 1985). This nest survival compared to that of nests in oth- was probably due to the extended 1997±1998 er plants (0.9356 Ϯ 0.0002 vs. 0.9409 Ϯ breeding season. Considering all species that 0.0005, respectively; Hensler and Nichols test, breed in this area of the Monte Desert, the Z ϭ 0.2, P Ͼ 0.05; Mezquida 2000). The in- Crested Gallito was one of the earlier nesting frequent use of chanÄar for nest support in re- species (i.e., mean egg laying date was con- lation to its availability may re¯ect the scar- sistently earlier than the average date of egg city of large individuals of these plants suit- laying for the entire avian assemblage during able for gallitos. All chanÄar used by gallitos the four years of study; Mezquida 2000). Gen- were Ͼ2.5 m tall, but only 25% (n ϭ 122) of erally, all species of Rhinocryptidae begin to chanÄar in a random sample were Ͼ2.5 m lay eggs early in the breeding season, usually (Mezquida 2000). It appears that small plants September through October, but as early as of this species do not provide adequate sup- late August (Goodall et al. 1957, Fraga and port for the nest of the Crested Gallito. Narosky 1985, FjeldsaÇ and Krabbe 1990). The mean maximum length and breadth of The Crested Gallito preferentially used Crested Gallito eggs in NÄ acunÄaÂn observed atamisque for nest support in NÄ acunÄaÂn. Per- during this study were less than those reported eyra (1951) and Fraga and Narosky (1985) found some nests in chanÄar in other areas of by Fraga and Narosky (1985; 29.0 Ϯ 0.4 mm Mendoza Province. Other nest supporting ϫ 21.5 Ϯ 0.2 mm, n ϭ 32 eggs in 8 refer- plants reported in western Argentina include ences, respectively; t77 ϭ 2.9, P Ͻ 0.01 for romerillo (Senecio spp.) and palmera (Trith- length and t77 ϭ 2.2, P Ͻ 0.05 for breadth). rinax spp.; Pereyra 1951, Ochoa 1962), which Mean egg mass was 0.4 g less than that re- are not present in NÄ acunÄaÂn. Atamisque is a ported by SchoÈnwetter (1967) and Fraga and tall shrub with dense foliage and small thorns Narosky (1985; n ϭ 12 and 5 eggs, respec- that seems to provide support and conceal- tively). These differences could be due to geo- ment for the large nest of the Crested Gallito. graphic variation in adult body mass. For in- Similarly, Eugralla paradoxa, another species stance, mean body mass of six adults on the of Rhinocryptidae that builds globular nests in Reserve of NÄ acunÄaÂn was 57.0 g (J. L. de Cas- trees and shrubs, nests in thorny and dense enave, pers. comm.) while adult body mass 108 THE WILSON BULLETIN • Vol. 113, No. 1, March 2001 reported by Navas and Bo (1986) in La Pampa FRAGA,R.AND S. NAROSKY. 1985. Nidi®cacioÂn de las Province averaged 63.6 g (n ϭ 4). aves ( a Cinclidae). Average clutch size for the species (Fraga Asoc. OrnitoloÂgica del Plata, Buenos Aires, Ar- gentina. and Narosky 1985) was the same (2.2 Ϯ 0.1 GOODALL, J. F., A. W. JOHNSON, AND R. A. PHILIPPI. eggs, n ϭ 10) as in my study, with 2 eggs the 1957. Las aves de Chile, Tomo I. Platt Establ. most common clutch size. This clutch size ap- Gra®c., Buenos Aires, Argentina. pears to be typical in Rhinocryptidae (Yom- LAZO,I.AND J. ANABALO N. 1991. Nesting of the Com- Tov et al. 1994). Wetmore (1926) reported two mon Diuca Finch in the central Chilean scrub. eggs of Shiny Cowbird (Molothrus bonarien- Wilson Bull. 103:143±146. MARONE, L. 1992. Estatus de residencia y categoriza- sis) in one nest of Crested Gallito in RõÂo Ne- cioÂn tro®ca de las especies de aves en la Reserva gro Province (Argentina) but, in spite of the de la Biosfera de NÄ acunÄaÂn, Mendoza. Hornero 13: presence of Shiny Cowbird in our study area 207±210. (Marone 1992), no parasitism of Crested Gal- MEZQUIDA, E. T. 2000. EcologõÂa reproductiva de un lito nests was observed. Brood parasitism by ensamble de aves del desierto del Monte central, Shiny Cowbird of any bird species was only Argentina. Ph.D. diss., Univ. AutoÂnoma, Madrid. NAROSKY,T.AND D. YZURIETA. 1987. GuõÂa para la sporadically observed during the four years of identi®cacioÂn de las aves de Argentina y Uruguay. study (Mezquida 2000), apparently a conse- Assoc. OrnitoloÂgica del Plata, Buenos Aires. quence of the low density of cowbirds in nat- NAVAS,J.R.AND N. A. BO . 1986. Notas sobre una ural habitats of the Reserve of NÄ acunÄaÂn. coleccioÂn de aves del Parque Nacional Lihue Cal- el, La Pampa, Argentina. Hornero 12:250±261. ACKNOWLEDGMENTS OCHOA, D. 1962. Nidi®cacioÂn de algunas aves de San Luis. Nuestras Aves 1:8±10. I thank L. Marone, F. Milesi, J. L. de Casenave and PEREYRA, J. A. 1951. Avifauna Argentina. Hornero 9: V. R. Cueto for their advice and help throughout the 291±347. work. Comments by L. Marone, M. H. Rosenberg, G. RIDGELY,R.S.AND G. TUDOR. 1994. The birds of H. Rosenberg, and two anonymous reviewers greatly South America. Vol. II. the suboscine . improved the manuscript. I acknowledge Programa Univ. Texas Press, Austin. MUTIS del Instituto de CooperacioÂn Iberoamericana SCHOÈ NWETTER, M. 1967. Handbuch der oologie. Lief. for providing ®nancial support while I conducted re- 14. Akademie-Verlag, BerlõÂn, Germany. search in Argentina. Field work was partially funded SMYTH, C. H. 1928. DescripcioÂn de una coleccioÂn de by Sigma Xi and MAB-UNESCO. This is Contribution huevos de aves Argentinas, II. Hornero 4:125± No. 15 of the Desert Community Ecology Research 152. Team (Ecodes), UF&EV, IADIZA. WETMORE, A. 1926. Observations on birds of Argen- tina, Paraguay, Uruguay, and Chile. U.S. Natl. LITERATURE CITED Mus. Bull. 133. YOM-TOV, Y., M. I. CHRISTIE, AND G. J. IGLESIAS. 1994. FJELDSAÇ ,J.AND N. KRABBE. 1990. Birds of the high Clutch size in passerines of southern South Amer- Andes. Apollo Books, Svendborg, Denmark. ica. Condor 96:170±177.