The Wilson Journal of Ornithology 120(1):176–180, 2008

USE OF CLAY LICKS BY MAROON-FRONTED PARROTS (RHYNCHOPSITTA TERRISI) IN NORTHERN MEXICO ´ S-PEN ˜ A,1,2 SONIA GABRIELA ORTIZ-MACIEL,1 RENE A. VALDE SIMON O. VALDEZ JUAREZ,1 ERNESTO C. ENKERLIN HOEFLICH,1 AND NOEL F. R. SNYDER1 ABSTRACT.—Geophagy has been documented in many species of birds, including many parrots, and its proposed functions include detoxification of dietary poisons, mineral supplementation, and acid buffering. Most geophagy reports involve tropical South American species; we present the first published report of clay-lick use by the Maroon-fronted Parrot (Rhynchopsitta terrisi), a species inhabiting high elevation temperate pine-oak (Pinus spp.–Quercus spp.) forest of the Sierra Madre Oriental. Thirty-six observation sessions were made at the four dispersed licks known from the restricted breeding range of this species. All known licks were near valley bottoms far below most nesting cliffs. Parrot visitations to ingest clay were characteristically in groups and the average number of parrots per group was nine individuals. Group visits averaged 18.3 min in duration and peaked between 0900 and 1100 hrs. The total number of parrots visiting licks during any day represented only a fraction of the known population of the species, suggesting that unless additional licks have yet to be discovered, visits of individuals to licks are relatively infrequent. Received 18 September 2006. Accepted 22 May 2007.

Geophagy is known primarily in herbivorous vertebrates including many ungulates, primates, elephants, reptiles, and a great diversity of birds (Emmons and Stark 1979, Jones and Hanson 1985, Izawa 1993). In birds, the trait has been described in cracids, corvids, pigeons, grouse, cassowaries, and hornbills (Prendergast and Boag 1970, Emmons and Stark 1979, Diamond et al. 1999), but is perhaps best known in parrots, where colorful aggregations of many species assemble at some of the earthen cliffs overlooking tributaries of the Amazon River. For example, hundreds of individuals of more than 20 parrot species are known to use licks overlooking the Tambopata River in the Tambopata-Candamo Reserve in Peru (Munn 1994, Brightsmith and Aramburu´ 2004). Other well known licks are in Manu National Park and along the Madre de Dios River of Peru (Gilardi et al. 1999); in Bolivia, ⬎1,000 individuals of at least six species have been observed at a lick in the Valle de la Luna (Mee et al. 2005), while other licks occur in Amazonian regions of Colombia, Ecuador, and Brazil (Izawa 1993, Kyle 2001). Geophagy is also known for Grey Parrots (Psittacus erithacus) in the Congo Basin forest (May 2001) and a variety of Asian species 1 Centro de Calidad Ambiental, ITESM, CEDES 5ⴰpiso, Avenida, Eugenio Garza Sada 2501 sur CP 64849, Monterrey, N.L. Me´xico. 2 Corresponding author; e-mail: [email protected]

in Papua, New Guinea (Diamond et al. 1999). Other observations of parrots eating soil have involved Lear’s Macaws (Anodorhynchus leari) on their nest cliffs in eastern Brazil, Red-fronted Macaws (Ara rubrogenys) on their nest cliffs in Bolivia, and cockatoos ingesting soil in a city park in Australia (J. D. Gilardi, pers. comm.). A variety of functions has been suggested for clay ingestion including gaining of mineral supplements, binding of toxic materials in diets, and regulation of pH in gut contents (Diamond et al. 1999, Gilardi et al. 1999). Studies by Gilardi et al. (1999) and Brightsmith and Aramburu´ (2004) in Peru suggest that both mineral supplementation and cytoprotection from secondary poisons in plant foods may be especially important functions. Clay ingestion has not been well documented for parrots in Mexico. There have been observations suggesting ingestion of soil by Military Macaws (Ara militaris) in northeastern and southwestern Mexico (Juan Vargas and Carlos Bonilla, pers. comm.), and Thick-billed Parrots (Rhynchopsitta pachyrhyncha) and Lilac-crowned Parrots (Amazona finschi) in northwestern Mexico (Juan Vargas, pers. comm.). The trait was first clearly recognized in the Maroon-fronted Parrot (Rhynchopsitta terrisi) in 1995 at two mudcliff sites still in use by the species today (NFRS). The objective of our study was to document basic features of clay-lick use by

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the Maroon-fronted Parrot during the breeding season, quantifying such features as group size, daily peaks in activity, and associated behaviors during clay ingestion. METHODS We observed four clay licks from June to September 2005 used by Maroon-fronted Parrots in 12, 3-day visits. All licks were in the Sierra Madre Oriental west and southwest of Monterrey, Nuevo Leon and were well distributed in the breeding range of the species in Nuevo Leon and Coahuila (Macias-Caballero 1998). Nesting of Maroon-fronted Parrots is mainly colonial and is only known to occur in natural cavities in vertical limestone cliffs. The parrots occur in this area only during the summer breeding season and migrate south in the Sierra Madre Oriental for the remainder of the year. We do not know if other licks occur in breeding and wintering areas of the species; however, coverage of the breeding area has been sufficiently intensive, especially through interviews of local residents, that we believe most licks in this region have been located. Two of the licks (Santa Cruz and Santa Rosa) are in Nuevo Leon. The other two (El Temporal and Ultimagua) are in Coahuila. Topographically, all four licks are close to valley bottoms in mud cliffs overlooking seasonal streams. None of the four licks is higher than 40 m above stream level and all are between 1,600 and 1,800 m above sea level. The most important nest cliffs of the species are at higher elevations (2,500–3,000 m above sea level). The climate of the study area in the northern Sierra Madre Oriental corresponds to temperate subhumid forest with summer rains predominant. The annual temperature average is 14⬚ C, with a range of 0 to 34⬚ C. The average annual precipitation is 600 mm of which 370 mm occurs between June and September. The vegetation is predominantly pine-oak (Pinus spp.–Quercus spp.) forest. The Maroonfronted Parrot primarily subsists on pine seeds of several species (mainly Pinus cembroides) with some use of acorns and agave seeds (Macias-Caballero et al. 1996). Much of this diet is considered to be chemically well defended with tannins (Wong 2007). Clay licks were observed with binoculars and/or telescopes between 0700 (sunrise) and 1700 hrs (before sunset) from 50 to 100 m,

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depending on topography and availability of suitable viewing sites. We recorded the number of parrots arriving at the clay licks, time of arrival, time spent eating clay per flock, weather, and notes about their behavior and/ or predator activity. We estimated the average number of parrots per flock that consumed clay and the average time these flocks were at clay licks. RESULTS Behavior.—Parrots usually arrived at clay licks in small groups (1–5 birds) giving typical flight vocalizations. The birds perched in nearby trees prior to landing at the clay cliffs, possibly assessing their surroundings for natural enemies. The first bird to land at the cliff was generally nervous in demeanor and normally did not begin feeding until joined closely by other parrots (within the next 2 min). During feeding, parrots flew to and from the lick regularly to change location on the cliff or to increase spacing with other parrots. We noted some parrots remained alert while others fed. The alert posture switched from one individual to another over time and, occasionally, the entire group on the cliff took flight simultaneously when one individual uttered a sharp alarm call. Feeding on soil typically occurred just below the top of the low cliffs, allowing the birds to quickly gain speed in leaving the cliffs by losing altitude. Sites used by parrots for ingesting clay showed the typical bird-created horizontal grooves, ledges, and hollows known for parrot clay licks in other regions and following particular soil horizons, which can be an indicator of preferred soils. Periods of Clay Consumption.—Use of licks occurred throughout the day with the exception of the last 2 hrs in late afternoon (1500–1700 hrs). Use was greatest during morning and declined during the afternoon (Fig. 1). Peak use occurred in late morning (0900–1100 hrs), although at one lick the largest number of birds was observed between 0700 and 0900 hrs. The number of birds at another lick was equal between 0700–0900 and 0900–1100 hrs (Table 1). Group Size and Number of Parrots at Licks.—Thirty-six groups of parrots were recorded in 12 days of observation with an average of three group visits per day for each of

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FIG. 1. Time of feeding (all observations) by Maroon-fronted Parrots at clay licks, Sierra Madre Oriental, Mexico (approx. sunrise at 0700 hrs and sunset at 1800 hrs).

the four clay licks (Table 1). The maximum simultaneous count of parrots at a lick was 28 and the maximum daily total for any lick was 63 individuals (in 5 groups). We recorded 326 birds eating clay and the average daily total was nine parrots per lick. These totals comprised only a small fraction of the estimated total parrot population (based on roost counts to be ⬃3,500 individuals at the time of the study). Duration of Time at Licks.—Groups of parrots stayed on the cliffs from 1 to 52 min (Table 2) with an average of 18.3 min per group visitation. The averages are for groups and not for individuals, many of which spent significant amounts of time during feeding sessions in alert postures. DISCUSSION The Maroon-fronted Parrot exhibited a strong preference for use of clay licks in late morning (0900–1100 hrs) in contrast to the temporal use of licks by parrots in tropical America. The main use period at tropical American licks is during the first hour after dawn (Brightsmith 2004; Mee et al. 2005; J. D. Gilardi, pers. comm.). Large macaws and

TABLE 1.

some parakeets have their main activity in late morning and afternoons (Brightsmith 2004). Maroon-fronted Parrots also visit licks in early morning, but the emphasis on late morning visitations suggests clay ingestion followed first feedings. We are unsure if additional clay licks exist in the Maroon-fronted Parrot range. However, interviews of local residents and knowledge that all known licks were in low-elevation sites of relatively easy access, suggest the four known licks could represent all licks in use by the parrot population or at least those they most used and frequented. This possibility is also suggested by the dispersed distribution of the licks relative to known nesting colonies of the species. Twenty-one nesting colonies are presently known for the species (MaciasCaballero 1998) and the greatest distance from known colonies to the nearest lick is 17.5 km. This distance compares with distances of 16 km estimated for parrots flying to and from licks in Peru (Brightsmith 2004). Ortiz-Maciel (2000) estimated individual Maroon-fronted Parrots flew as far as 23 km from breeding colonies and the known distribution

Numbers of Maroon-fronted Parrots at clay licks in the Sierra Madre Oriental, Mexico. Numbers of parrots

Time (hrs)

Sta. Cruz

Sta. Rosa

Temporal

Ultimagua

Totals

Range

0700–0900 0900–1100 1100–1300 1300–1500 1500–1700 Totals

6 42 21 4 0 73

44 34 22 10 0 110

8 70 0 3 0 81

25 25 12 0 0 62

83 171 55 17 0 326

2–16 2–28 1–8 3–6 0 1–28

x¯

⫾ SD

Groups (n)

8.3 11.4 7.8 4.2 0 9

⫾4.4 ⫾7.8 ⫾5.8 ⫾1.2 0 ⫾6.4

10 15 7 4 0 36

Valde´s-Pen˜a et al. • MAROON-FRONTED PARROTS

TABLE 2. Time (min) of Maroon-fronted Parrots at clay licks, Sierra Madre Oriental, Mexico. Time at clay licks (min) Clay lick

Groups (n)

Range

x¯

Sta. Cruz Sta. Rosa Temporal Ultimagua Totals

8 15 7 6 36

1–49 1–52 9–31 5–48 1–52

21.1 15.6 19.1 20.3 18.3

⫾ SD

⫾ ⫾ ⫾ ⫾ ⫾

15.89 12.05 8.15 17.85 13.27

of clay licks could serve all known breeding colonies without need for additional licks. The two largest known Maroon-fronted Parrot colonies, comprising about 83% of the breeding population (in 2005), are 15.5 and 9.25 km from the nearest licks, and separated from the licks by 1,200 m elevation. The cost of flying to and from licks may cause parrots to delay visits to licks until late morning after their first feedings. Ortiz-Maciel (2000) indicated that peak morning movements of Maroon-fronted Parrots occurred between 0600 and 0900 hrs. The relatively low numbers of parrots visiting licks on any day strongly suggests that individual parrots may visit licks infrequently. Visits of the species to favored water sites for drinking, at times attracts up to 1,000 individuals per day (NFRS). Observations of the closely-related Thick-billed Parrot (Snyder et al. 1999) suggest daily drinking periods for individuals—a dramatic contrast to the apparent low frequency of clay ingestion in Maroon-fronted Parrots. Maroon-fronted Parrot groups at licks averaged nine individuals and spent an average of 18.3 min at the licks. In South America, where many parrot species use the same licks and group sizes are often much larger, the average time individuals spent at licks ranged from 28.7 to 47.4 min for diverse species (Burger and Gochfeld 2003). The behavior of individual Maroon-fronted Parrots at licks was generally similar to that described for other species. Given the average of three groups per day with nine birds at each clay lick (108 birds), we hypothesize parrots use the lick once every 2.7 days based on a breeding population of ⬃300 birds in 2005. This hypothesis should be tested with uniquely marked parrots to ob-

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tain a more accurate average and the extent of individual variation in visitation rates. Maroon-fronted Parrots have a diet of pine seeds and acorns which is rich in protein, carbohydrates, and fiber (Fonseca 2003). Wong (2007) found that pinion seeds (mainly Pinus cembroides) eaten by Maroon-fronted Parrots had low levels of Na, Ca, Mn, and S; these minerals occurred in high levels in consumed clay. Wong (2007) also found that clay had minerals such as kaolin, smectite, and micas that can absorb secondary compounds such as polyphenols and alkaloids suggesting the clays could also buffer acids. These findings suggest that parrots consume clay to help in absorption of dietary toxins, mineral supplements, and acid buffering capacity as also demonstrated by Gilardi et al. (1999). We recommend that areas used for geophagy be included as important sites for conservation of Maroon-fronted Parrots and that future studies of their ecology continue to document geophagy activity by including more visits to the clay licks. Future activities should involve local people to implement ecotourism in these areas. ACKNOWLEDGMENTS We thank the team work of the Centro de Calidad Ambiental at ITESM Campus Monterrey, without them this work could not have happened. Their friendship and desire to work for conservation of psitacids contributed to our success. We also thank Jamie Gilardi, Eduardo In˜igo, and Donald Brightsmith for comments and revision of this paper, and CONACYT, and the National Commission of Natural Protected Areas of Mexico (CONANP) for financial support. We also thank all the volunteers that collaborated in field work and the local people whose hospitality made our field stays especially pleasant.

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