Short Communications

The Wilson Journal of Ornithology 118(1):99±101, 2006

Provisioning of Fledgling Conspeci®cs by Males of the Brood-parasitic klaas and C. caprius

Irby J. Lovette,1,4 Dustin R. Rubenstein,1,2,3 and Wilson Nderitu Watetu3

ABSTRACT.ÐAlthough post-¯edging care by adult Over the past century, there have been nu- males seems unlikely in species that are obligate, merous observations of male Chrysococcyx interspeci®c brood parasites, there have been numer- cuckoos feeding conspeci®cs that were ous reports of adult male Chrysococcyx cuckoos ap- parently feeding conspeci®c young. Most researchers thought to be ¯edglings (Moreau 1944, Fried- currently view these observations with skepticism, in mann 1968, Iversen and Hill 1983, Rowan large part because Chrysococcyx and other spe- 1983). In a literature review of provisioning cies engage in courtship feeding, and it is possible that behavior in brood parasites, Lorenzana and ®eld observers could mistake adult females receiving Sealy (1998) found 5 records of nestling or food from courting males for ¯edglings, especially giv- en the similar appearances of females and juveniles. ¯edgling provisioning by Klaas's Cuckoo Here, we report an observation of an extended provi- males and 11 such records for Diederik Cuck- sioning bout by an adult male Klaas's Cuckoo (C. oo males; Friedmann (1968) discusses 12 and klaas) feeding a conspeci®c individual with juvenile 15 such records, respectively, including some plumage and behavior, and we summarize our obser- anecdotal reports. There is apparently only vations of similar occurrences in the one equivalent report of a female Chrysococ- (C. caprius) in Kenya. We suggest that the available evidence indicates that male provisioning, and hence cyx cuckoo provisioning ¯edglings, and in that potential parental care, is present in these brood-para- case, both the female and young were captive sitic cuckoos at a higher frequency than currently rec- (Millar 1926, Lorenzana and Sealy ognized. The mechanism that causes males to associate 1998). Historically, a number of researchers with ¯edglings is unknown, but warrants further study. (e.g., Moreau 1944, Friedmann 1968) consid- Received 20 December 2004, accepted 19 September 2005. ered parental care to be common in African Chrysococcyx cuckoos and believed that the behavior might be a primitive condition as- sociated with a relatively recent evolutionary The Chrysococcyx comprises 15 spe- transition to brood parasitism. As researchers cies of small, Old World cuckoos (Sibley and continued to document the prevalence of Monroe 1990), of which all are thought to be courtship feeding in these and other cuckoo obligate brood parasites (Davies 2000). species, more recent authorities (e.g., Rowan Klaas's Cuckoo (C. klaas) has a wide distri- 1983, Irwin 1988, Lorenzana and Sealy 1998, bution in sub-Saharan Africa, where it is Davies 2000) have suggested that the behavior known to parasitize a large number of passer- is either misdirected courtship feeding or the ine host taxa, oftenÐbut not exclusivelyÐ result of human observers misidentifying species of Sylviidae and Nectarinidae (Irwin adult females as ¯edglings. In practice, these 1988). Similarly, the Diederik Cuckoo (C. ca- and other possibilities are dif®cult to exclude. prius) breeds throughout much of sub-Saharan Although the plumages of adult African Chry- Africa and has a broad range of hosts, pri- sococcyx are highly sexually dimorphic, it is marily species of (Irwin 1988). dif®cult to distinguish females from juveniles in the ®eld (Rowan 1983). 1 Cornell Lab. of Ornithology, 159 Sapsucker Here, we report an observation of an ex- Woods Rd., Ithaca, NY 14850, USA. tended provisioning bout by an adult male 2 Dept. of Neurobiology and Behavior, Cornell Klaas's Cuckoo feeding a conspeci®c individ- Univ., Seeley G. Mudd Hall, Ithaca, NY 14853, USA. 3 Mpala Research Centre, Box 555, Nanyuki, Ken- ual with juvenal plumage and behavior, and ya. we summarize our observations of similar oc- 4 Corresponding author; e-mail: [email protected] currences in the Diederik Cuckoo. These ob- 99 100 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006 servations add to the body of evidence sug- white patch behind the eye and a white throat gesting that male Chrysococcyx cuckoos may marked with substantial, dark barringÐplum- engage in intensive provisioning of juveniles. age characters more typical of juveniles (Irwin 1988). KLAAS'S CUCKOO Beginning at 10:08 UTCϩ3 on 15 August DIEDERIK CUCKOO 2004, IJL, DRR, and WNW observed an adult On 28 May 2002 at 08:23, WNW observed male (by plumage) Klaas's Cuckoo in Lake a male Diederik Cuckoo feeding an apparent Nakuru National Park, Kenya (00Њ 22Ј S, 36Њ ¯edgling (based on plumage) at the Mpala Re- 03Ј E). This bird was foraging at an extremely search Centre, Laikipia, Kenya (00Њ 17Ј N, rapid rate of movement in the open canopy of 36Њ 54Ј E). The ¯edgling was perched about 3 a large yellow-barked acacia tree (Acacia xan- m above ground in a Balanites aegyptica tree. thophloea). After watching the bird for a few During 15 min of observation, the adult fed minutes, we observed it deliver food to a sec- the ¯edgling at least four times and continued ond, sedentary cuckoo in the same tree. We to do so when the observer left the area. On noted the time, and for the next 26 min, we 19 May 2003 at 10:15, WNW noted similar were able to keep both cuckoos under constant behavior at a site 100 m from that of the ®rst focal observation with at least one observer observation. During this observation, an adult following each bird. This is apparently the male Diederik Cuckoo gleaned from longest-duration period of potential ¯edgling long grass and fed them to a ¯edgling (based provisioning reported for Chrysococcyx on plumage) perched on a nearby acacia. We (Friedmann 1968). observed the male make six feeding trips be- During our observation, the adult male fore cattle ¯ushed the birds. cuckoo continued to forage rapidly within an approximate 40-m radius around the second DISCUSSION cuckoo. The male returned to the second Based on the posture, behavior, and plum- cuckoo 18 times while carrying food items, age of the Klaas's Cuckoo that we observed all of which appeared to be 1- to 3-cm-long being fed by an adult male, it seems highly lepidopteran larvae gleaned from the foliage likely that it was a recently ¯edged bird rather and bark of the acacia. On 16 of the 18 visits, than an adult female being courted. We also the second, more sedentary bird accepted and noted that the adult male engaged in intensive ate the caterpillar. On each visit, the adult (and, presumably, energetically costly) forag- male presented the food with his tail slightly ing for an extended period in order to provi- cocked, but we observed no other conspicuous sion this individual. Friedmann (1968) consid- postures or behaviors potentially related to ered provisioning bouts as long as 15 min as courtship. No copulations or attempted copu- ``suggestive of the fact that the catering adult lations occurred. was not merely indulging in courtship feed- During our observation, the presumed ju- ing.'' Our observation of an intensive provi- venile moved among four perches, ¯ying 3±4 sioning period of nearly twice that duration m each time. These ¯ights were notably more further supports this interpretation. In contrast, ¯uttery than those of the adult male and ap- courtship feeding in Chrysococcyx typically peared typical of the weak ¯ight exhibited by involves a series of stereotyped behaviors that recently ¯edged birds. While perched, this we did not observe: the male's presentation of bird also assumed the ``¯uffed'' posture typi- food while simultaneously cocking his head cal of recent ¯edglings, and it remained sta- and vibrating his wings and tail, postural bow- tionary between most provisioning visits. The ing movements by the male, vocalizations by observation ended when the presumed juve- the male or both individuals, or (in some cas- nile made a similar, but slightly longer ¯ight es) subsequent copulation (Irwin 1988). into denser foliage and disappeared from our When considered in concert, our observa- sight. Although the plumages of female and tions and those in dozens of previous reports immature Klaas's Cuckoos are variable and describing equivalent behaviors suggest that overlap (Irwin 1988), we noted at the time males of several African Chrysococcyx cuck- that the bird being provisioned had a distinct oos may provision ¯edglings regularly. Post- SHORT COMMUNICATIONS 101

¯edging associations of adults and offspring LITERATURE CITED also have been documented in other brood- parasitic taxa, such as the Brown-headed DAVIES, N. B. 2000. Cuckoos, , and other cheats. T. & A.D. Poyser, London, United King- (Molothrus ater; Hahn and Fleischer dom. 1995). Indeed, previous reports have docu- FRIEDMANN, H. 1968. The evolutionary history of the mented male Klaas's and Diederik cuckoos genus Chrysococcyx. U.S. National Museum Bul- provisioning both pre-volant young and mul- letin, no. 265, Smithsonian Institution, Washing- tiple ¯edglings (Moreau 1944, Friedmann ton, D.C. 1968, Lorenzana and Sealy 1998), thus ex- HAHN,D.C.AND R. C. FLEISCHER. 1995. DNA ®nger- print similarity between female and juvenile cluding misidenti®cation of adult females as Brown-headed Cowbirds trapped together. suf®cient explanation for this behavior. We Behaviour 49:1577±1580. speculate that not only are females sometimes IRWIN, M. P. S. 1988. Order Cuculiformes. Pages 58± misidenti®ed as ¯edglings, but perhaps older 104 in Birds of Africa, vol. III (C. H. Fry, S. ¯edglings being provisioned by males are Keith, and E. K. Urban, Eds.). Academic Press, sometimes mistaken for females being court- London, United Kingdom. ed. If earlier reports were correct and provi- IVERSON,E.AND B. HILL. 1983. Diederik Cuckoo feeds ¯edgling of same species. Bee-eater 34:47. sioning of ¯edglings by adult males is rela- LORENZANA,J.C.AND S. G. SEALY. 1998. Adult brood tively common in the African Chrysococcyx, parasites feeding nestlings and ¯edglings of their it raises interesting questions about the genetic own species: a review. Journal of Field Ornithol- relatedness of the interacting individuals and ogy 69:364±375. their underlying social system. MILLAR, H. M. 1926. Golden Cuckoo, C. cupilus. South African Journal of Natural History 6:28±29. ACKNOWLEDGMENTS MOREAU, R. E. 1944. Food-bringing by African Bronze Cuckoos. Ibis 86:98±100. We thank M. Muchai and the many additional staff ROWAN, M. K. 1983. The doves, parrots, louries, and members of the Department of Ornithology, National cuckoos of Southern Africa. David Philip, Cape Museums of Kenya who have greatly facilitated our Town, South Africa. ®eld research in their country. We similarly acknowl- SIBLEY,C.G.AND B. L. MONROE. 1990. Distribution edge the Kenya Wildlife Service and the Mpala Re- and of birds of the world. Yale Univer- search Centre for allowing us to conduct this research. sity Press, New Haven, Connecticut.

The Wilson Journal of Ornithology 118(1):101±104, 2006

Widespread Cannibalism by Fledglings in a Nesting Colony of Black-crowned Night-Herons

Christina Riehl1,2

ABSTRACT.ÐI studied the diet and foraging be- enging. Isolated incidents of cannibalism among havior of ¯edgling Black-crowned Night-Herons (Nyc- Black-crowned Night-Herons have been reported pre- ticorax nycticorax) in a mixed-species nesting colony viously, but not on a colony-wide scale. Received 2 of Black-crowned Night-Herons and Snowy Egrets December 2004, accepted 19 September 2005. (Egretta thula) in New Orleans, Louisiana. In 1 of 5 years, cannibalism of nestlings that had fallen or climbed out of nests was common, accounting for 66 of 94 (70.2%) prey items taken by ¯edglings. Juveniles Many researchers have studied the diets of took younger conspeci®cs by both predation and scav- adult and nestling Black-crowned Night-Her- ons (Nycticorax nycticorax; Bent 1926, Palm- er 1962, Wolford and Boag 1971), but there 1 5500 Camp St., New Orleans, LA 70115, USA. 2 Current address: Dept. of Ecology and Evolution- are few data on the diet and foraging behavior ary Biology, Princeton Univ., Princeton, NJ 08544, of juveniles immediately after leaving the USA; e-mail: [email protected] nest. Here, I provide the ®rst report of wide- 102 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006 spread cannibalism and scavenging of conspe- er ¯edglings (see Noble et al. 1938 for a full ci®cs among ¯edglings in a nesting colony of description of territoriality in juvenile night- Black-crowned Night-Herons. herons). Fledglings rarely ventured into the water to hunt; rather, they spent most of their METHODS time foraging on the ground under active From 1 February to 18 July 2000, I moni- nests. Of 94 prey items that I saw juvenile tored a colony of Black-crowned Night-Her- night-herons consume, 66 (70.2%) were youn- ons on Ochsner Island, Audubon Park, New ger ¯edgling or nestling night-herons. I ob- Orleans, Louisiana (29Њ 56Ј N, 90Њ 8Ј W) as served juveniles feeding on both chicks that part of a long-term (1997±2001) study on re- they killed (n ϭ 20) and chicks that were al- productive success. Ochsner Island is a small ready dead when I began observations (n ϭ (600 m2) island in a man-made lagoon; the 46). Other prey items included ®sh (10.6%), distance between the island and the shore of frogs (8.5%), brown rats (Rattus norvegicus; the mainland is approximately 6 m. The is- 4.3%), carrion dropped from active nests land's vegetation is dominated by Chinese tal- (3.2%), Wood Duck chicks (Aix sponsa; lowtree (Sapium sebiferum) and live oak 2.1%), and a dead Snowy Egret nestling (Quercus spp.). In 2000, 143 pairs of Black- (1.1%). crowned Night-Herons and 10 pairs of Snowy Fledglings did not prey on chicks in nests Egrets (Egretta thula) nested on the island. or chicks perched in vegetation; they limited Nest height ranged from 1 to 7 m above their attacks to nestlings on the ground that ground. I recorded the diet and foraging be- had fallen or climbed out of nests. Adults de- havior of approximately 70 juvenile night-her- fended chicks in nests, but I never observed ons from ¯edging until the end of the breeding adults interfering with ¯edglings that were season, when the members of the nesting col- preying on chicks on the ground. Since older ony dispersed. Night-herons were considered night-heron nestlings often left the nest to to have ¯edged when they left the nest per- perch on nearby vegetation before ¯edging manently and were no longer fed by adults, at permanently, it was not always clear whether which point most were capable of clumsy victims were nestlings that had fallen from ¯ight. Prey items were identi®ed by direct ob- nests or younger ¯edglings that had just left servation of foraging night-herons. Observa- the nest. It is probable, however, that preda- tions were made from the mainland, from tion by ¯edgling night-herons increased mor- which approximately half of the nests in the tality rates of chicks that had climbed out of colony could be observed. I observed foraging the nest and would have otherwise been able juveniles for 546 hr. to climb to safety. Older nestlings in low nests (Ͻ1.5 m above ground) often climbed out of RESULTS the nest onto the ground before ¯edging, and Juvenile Black-crowned Night-Herons were were therefore more vulnerable to attacks than fed by parents until 45 Ϯ 3 (SD) days after nestlings in high nests. hatching (n ϭ 23). However, juveniles were Small, weak, and moribund chicks were at- able to climb out of the nest and onto sur- tacked more frequently than healthy-looking rounding vegetation as early as 30 days after nestlings near the age of ¯edging. The victims hatching, returning to the nest when a parent were approximately 50±70% of the size of approached with food. At 35 days, juveniles ¯edglings and appeared dif®cult to kill and readily left their nests, often climbing out of consume. Fledglings killed younger conspe- the nest to solicit food from a nearby parent ci®cs by striking them with their bills for up or unrelated adult night-heron. to 1 hr or more, and then consumed them by Juveniles remained on the island for 1±3 repeatedly striking the carcasses and labori- weeks after leaving the nest permanently, ously tugging small pieces of meat from them. forming small groups of one to four individ- Older ¯edglings were particularly skilled at uals from the same nest, or neighboring nests. preying on nestlings and appeared to focus Each group or lone individual occupied a their foraging attempts on nestlings to the ex- small (7±9 m2) territory on the ground and clusion of other prey. When a ¯edgling found defended the area from passing adults and oth- an undefended nestling and began to attack it, SHORT COMMUNICATIONS 103 other ¯edglings usually came to ®ght over the found that juveniles sometimes climbed back victim. In one case, I observed ®ve ¯edglings to the nest in the ®rst 2±3 days after ¯edging, attack and consume a 15-day-old nestling that and were usually fed by the parents. After 3 had fallen from its nest. days post-¯edging, ¯edglings on the ground often grabbed the bills of passing adults in an DISCUSSION attempt to stimulate them to regurgitate food, Black-crowned Night-Herons are among but were almost always unsuccessful. the most opportunistic of North American her- Fledglings also seemed unable to ®sh ef®- ons. They employ several different foraging ciently in the deep water surrounding the is- behaviors (Kushlan 1976) and consume a land, at least for the ®rst 7 or 8 days after wide variety of prey, including ®sh, mollusks, ¯edging. I frequently observed ¯edglings in insects, reptiles, amphibians, rodents, birds, the water striking at ¯oating sticks and pieces , carrion, refuse, and plants (Hancock and of leaves, but they rarely captured live prey. Kushlan 1984, Davis 1993). Night-herons will Fledglings occasionally picked up prey alter their foraging methods to concentrate on dropped by nestlings in active nests; on one locally abundant resources, including mice occasion, a ¯edgling climbed into a low nest (Allen and Mangels 1940), ®sh (Spanier and pulled a ®sh from the bill of the ¯edgling 1980), and amphibians (Wetmore 1920). They to which it had just been delivered. Adults, by have also been reported to systematically ex- contrast, were never observed feeding on dead ploit rookeries of other colonially nesting nestlings or other carrion, suggesting that they birds, including Common Terns (Sterna hirun- were more skilled at catching higher-quality, do; Marshall 1942, Collins 1970, Shealer and live prey. Kress 1991) and Franklin's Gulls (Larus pi- Although I spent similar amounts of time pixcan; Wolford and Boag 1971). Kale (1965) observing the same rookery each year (1997± reported an instance of adult night-herons in 2001), cannibalism among Black-crowned a colony preying opportunistically on White Night-Heron ¯edglings was prevalent only in Ibis (Eudocimus albus) and Great Egret (Ar- 2000. I observed night-heron ¯edglings feed- dea alba) chicks from the same mixed-species ing on dead night-heron and egret chicks only rookery, noting that ibis and egret chicks from twice in 1998 and once in 2001. The species neighboring nests constituted a major food composition of the nesting colony was fairly source for night-heron chicks. Published re- constant across years, comprising 120±150 ports of night-herons feeding on conspeci®cs, pairs of Black-crowned Night-Herons and 5± however, are limited to Wolford and Boag's (1971) report of a night-heron nestling that 10 pairs of Great Egrets and Snowy Egrets; was regurgitated by another nestling. Williams thus, the level of competition for food among and Nicholson (1977) reported a suspected in- ¯edglings on the island should not have been stance of brood reduction in the Black- elevated in 2000. In other years, ¯edgling di- crowned Night-Heron, but did not ®nd evi- ets were dominated by ®sh and frogs. How- dence of cannibalism. ever, it is dif®cult to compare prey composi- There is virtually no information on the for- tion across years because I observed far fewer aging behavior of night-heron ¯edglings dur- prey captures in other years, possibly because ing the period immediately after they leave the juvenile Black-crowned Night-Herons may nestÐafter the adults have stopped feeding forage mostly at night. them but before they become adept at catching It is possible that cannibalism rates were their own prey. Lorenz (1938) and Palmer exceptionally high in 2000 because local (1962) reported that ¯edglings move through shortages of ®sh or other live prey forced the colony and are able to beg food from any ¯edglings to seek alternate food resources, but adult; however, Finley (1906) and Noble et al. I was unable to document such a shortage. A (1938) found that adults do not feed juveniles food shortage would have affected the diet on the ground. Data on the composition of and foraging patterns of ¯edglings more than ¯edgling diet are scarce, possibly because re- adults and nestlings, since adults often left the cently ¯edged juveniles may forage at night nesting colony to forage while ¯edglings re- (Rockwell 1910, Davis 1993). In this study, I mained on the island. 104 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006

ACKNOWLEDGMENTS of the International Ornithological Congress 8: 207±218. I am grateful to W. E. Davis, Jr., J. A. Kushlan, and MARSHALL, N. 1942. Night desertion by nesting Com- an anonymous reviewer for their helpful comments on mon Terns. Wilson Bulletin 54:27±31. the manuscript. NOBLE, G. K., M. WURM, AND A. SCHMIDT. 1938. So- cial behavior of the Black-crowned Night Heron. LITERATURE CITED Auk 55:7±40. PALMER, R. S. 1962. Handbook of North American ALLEN,R.P.AND F. P. M ANGELS. 1940. Studies of the nesting behavior of the Black-crowned Night Her- birds, vol. I: loons through ¯amingos. Yale Uni- on. Proceedings of the Linnean Society of New versity Press, New Haven, Connecticut. York 50±51:1±28. ROCKWELL, R. B. 1910. Some Colorado night heron BENT, A. C. 1926. Life histories of North American notes. Condor 12:113±121. marsh birds. U.S. National Museum Bulletin, no. SHEALER,D.A.AND S. W. KRESS. 1991. Nocturnal 135, Smithsonian Institution, Washington, D.C. abandonment response to Black-crowned Night- COLLINS, C. T. 1970. The Black-crowned Night Heron Heron disturbance in a Common Tern colony. Co- as a predator of tern chicks. Auk 87:584±586. lonial Waterbirds 14:51±56. DAVIS, W. E., JR. 1993. Black-crowned Night-Heron SPANIER, E. 1980. The use of distress calls to repel (Nycticorax nycticorax). The Birds of North night herons (Nycticorax nycticorax) from ®sh America, no. 74. ponds. Journal of Applied Ecology 17:287±294. FINLEY, W. L. 1906. Herons at home. Condor 8:35±40. WETMORE, A. 1920. Observations on the habits of HANCOCK,J.AND J. A. KUSHLAN. 1984. The herons birds at Lake Burford, New Mexico. Auk 37:393± handbook. Harper and Row, New York. 412. KALE, H. W., II. 1965. Nestling predation by herons in WILLIAMS,M.D.AND C. P. NICHOLSON. 1977. Obser- a Georgia heronry. Oriole 30(March):69±70. vations at a Black-crowned Night-Heron nesting KUSHLAN, J. A. 1976. Feeding behavior of North colony. Migrant 48:1±7. American herons. Auk 93:86±94. WOLFORD,J.W.AND D. A. BOAG. 1971. Food habits LORENZ, K. 1938. A contribution to the comparative of Black-crowned Night Herons in southern Al- sociology of colonial-nesting birds. Proceedings berta. Auk 88:435±437.

The Wilson Journal of Ornithology 118(1):104±106, 2006

First Report of Black Terns Breeding on a Coastal Barrier Island

Shawn R. Craik,1,3 Rodger D. Titman,1 AmeÂlie Rousseau,1 and Michael J. Richardson2

ABSTRACT.ÐBlack Terns (Chlidonias niger suri- neither chick survived beyond 4 days. Received 15 De- namensis) breed locally in freshwater wetlands across cember 2004, accepted 5 October 2005. the northern United States and central Canada, often building their nests over shallow water on a ¯oating substrate of matted marsh vegetation. Here, we report the ®rst nesting record of this species on a coastal bar- The North American subspecies of Black rier island. The nest, which consisted of two eggs laid Tern (Chlidonias niger surinamensis) breeds in a slight scrape of sand, was located on 6 July 2004 locally across the northern United States and in a large breeding colony of Common Terns (Sterna central Canada. Black Terns are semicolonial, hirundo) on Kelly's Island at Kouchibouguac National typically nesting in productive, shallow fresh- Park, New Brunswick, Canada. The observation also represents the current northeastern breeding limit for water marshes, semipermanent ponds, prairie this species in North America. Both eggs hatched, but sloughs, and along margins of lakes and rivers (Stewart and Kantrud 1984, Dunn and Agro 1995, Schummer and Eddleman 2003). Nests 1 Dept. of Natural Resource Sciences, McGill Univ., are generally placed in areas of calm water Ste-Anne-de-Bellevue, QC H9X 3V9, Canada. within stands of emergent bulrush (Scirpus 2 Dept. of Biological Sciences, Bishop's Univ., Len- noxville, QC J1M 1Z7, Canada. spp.), cattail (Typha spp.), bur-reed (Spargan- 3 Corresponding author; e-mail: ium spp.), or pickerelweed (Pontederia corda- [email protected] ta; Cuthbert 1954, Dunn 1979, Mazzocchi et SHORT COMMUNICATIONS 105 al. 1997). Nests are usually built over shallow Northumberland Strait from the shallow estu- water (0.5±1.2 m deep) on a ¯oating substrate ary-lagoon system of Kouchibouguac National of matted, dead marsh vegetation, ¯oating root- Park (Beach 1988). The island is composed of stalks and discarded pieces of wood, or musk- sand and is vegetated by extensive stands of rat feeding platforms; occasionally, nests are marram grass (Ammophila breviligulata); the built on non-¯oating substrates, including island's outer edge consists of a gently sloping muskrat lodges, ¯attened vegetation, and mud intertidal beach zone. The island supports a (Cuthbert 1954, Bergman et al. 1970, Dunn large breeding colony of Common Terns, 1979). Nests often consist of dead vegetation which included 1,041 nests counted in 2004 arranged in a compressed pile with a shallow (Parks Canada Tern Survey 2004). depression at the top (Dunn and Agro 1995). On 6 July 2004 at approximately 17:00 Black Terns use coastal habitats during mi- AST, after the entire tern colony at Kelly's Is- gration, winter, and in summer when non- land had ¯ushed and taken ¯ight, we identi- breeding birds aggregate in large ¯ocks (100ϩ ®ed a pair of adult Black Terns ¯ying above birds) on saltpans, marshes, estuaries, and the center of the island. One of the Black brackish wetlands (Dunn and Agro 1995). Re- Terns descended and landed, and we subse- ports of Black Terns breeding in marine areas quently identi®ed a Black Tern nest with two are extremely rare (Sirois and Fournier 1993). eggs laid in a slight scrape of sand. The long, In the mid-1990s, a single nest was found at oval eggs were noticeably smaller (ϳ34 ϫ 24 Seal Island National Wildlife Refuge (NWR), mm) than the subelliptical eggs in nearby Rockland, Maine (C. S. Hall pers. comm.), Common Tern nests (ϳ42 ϫ 31 mm; SRC and in both 2003 and 2004, two nests were pers. obs.). The Black Tern eggs were dark located at Machias Seal Island, New Bruns- olive and marked with dark brown dots and wick (C. M. Develin pers. comm.). The nests blotches, the density of which was greater at these marine sites consisted of a small near the large end. Nearby Common Tern eggs amount of dead vegetation in sparse common were generally cream colored and ®nely sheep sorrel (Rumex acetosella) and grasses, marked with brown and black dots. The Black or they were placed on a granite rock surface. Tern nest and many of the Common Tern nests Nests were located in large, mixed colonies of consisted of a small amount of dead vegeta- Common (Sterna hirundo) or Arctic (S. par- tion loosely lining a scrape made in the sand. adisaea) terns. The nest at Seal Island NWR Both species nested in areas of the island was ϳ30 m from the high-tide line, whereas where cover was sparse (5±15% marram the nests at Machias Seal Island were ϳ100 grass). Whereas Common Tern nests were m from water. All ®ve Black Tern nests in 0.5±30 m from the high-tide line, the Black marine areas failed to ¯edge young. Tern nest was 26.5 m from the water. Two The Canadian Maritime breeding popula- Common Tern nests were within 3 m of the tion of Black Terns was estimated to be 150 Black Tern nest. pairs (Erskine 1992), with southern New On 20 July at 17:20, we returned to the nest Brunswick representing the species' north- and found a newly hatched chick and a pip- eastern breeding limit in North America ping . The hatchling's down was predom- (Dunn and Agro 1995). Since 2000, however, inantly cinnamon and black, except for a Black Terns (Ͻ4 birds annually) have been white belly and a white mask over the eye and observed in mid- to late June with breeding cheek. A single adult Black Tern was ob- Common Terns on four coastal barrier islands served ¯ying 5±10 m directly above the nest. of Kouchibouguac National Park, New Bruns- On 24 July, we checked the nest again and wick. Surveys conducted from 2000 to 2003, found both chicks dead at the nest; one adult however, did not con®rm breeding (Christie et Black Tern was ¯ying 10±15 m above the is- al. 2004; E. Tremblay pers. comm.). land. The young were necropsied, but the Here, we report the ®rst evidence of Black cause of death was undetermined (S. McBur- Terns breeding on a coastal barrier island. Kel- ney pers. comm.). ly's Island (46Њ 50Ј N, 64Њ 55Ј W), 2 ha in size, Adult Common Terns at Kelly's Island is part of a 26-km crescent of barrier spits and readily exhibited aggressive displays toward islands that separate Kouchibouguac Bay of the the smaller Black Tern adults. Overt aggres- 106 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006 sion typically involved brief aerial chases and ysis. Kouchibouguac National Park, Environment attack by Common Terns as a Black Tern Canada-Parks, New Brunswick, Canada. adult approached and descended toward its BERGMAN, R. D., P. SWAIN, AND M. W. WELLER. 1970. A comparative study of nesting Forster's and nest. Common and Black terns occasionally Black terns. Wilson Bulletin 82:435±444. form mixed-breeding colonies elsewhere BURGER,J.AND M. GOCHFELD. 1991. The Common (Snow and Perrins 1998), and Common Terns Tern: its breeding biology and social behaviour. have been known to defend nesting territories Columbia University Press, New York. against other tern species, including Roseate CHRISTIE, D. S., B. E. DALZELL,M.DAVID,R.DOIRON, Terns (Sterna dougallii; Burger and Gochfeld D. G. GIBSON,M.H.LUSHINGTON,P.A.PEARCE, S. I. TINGLEY, AND J. G. WILSON. 2004. Birds of 1991, Nisbet 2002). Aggressive displays by New Brunswick: an annotated list. New Bruns- Common Terns, and the close proximity of wick Museum monographic series (natural sci- tern nests at Kelly's Island, may have com- ence), no. 10. Saint John, New Brunswick, Can- promised the survival of the Black Tern ada. chicks by preventing the adults from provid- CUTHBERT, N. L. 1954. A nesting study of the Black ing suf®cient food resources to their young, Tern in Michigan. Auk 71:36±63. resulting in dehydration or malnutrition (S. DUNN, E. H. 1979. Nesting biology and development of young in Ontario Black Terns. Canadian Field- McBurney pers. comm.). Nevertheless, our Naturalist 93:276±281. observations represent the ®rst con®rmed DUNN,E.H.AND D. J. AGRO. 1995. Black Tern (Chli- breeding of Black Terns on the barrier islands donias niger). The Birds of North America, no. of Kouchibouguac National Park and repre- 147. sent the northeastern breeding limit for this ERSKINE, A. J. 1992. Atlas of breeding birds of the species in North America. Maritime Provinces. Nimbus Publishing and Nova Scotia Museum, Halifax, Nova Scotia, Canada. MAZZOCCHI, I. M., J. M. HICKEY, AND R. L. MILLER. ACKNOWLEDGMENTS 1997. Productivity and nesting habitat character- We are grateful to Kouchibouguac National Park, istics of the Black Tern in northern New York. especially E. Tremblay, for providing logistical and Colonial Waterbirds 20:596±603. ®eld support. We appreciate information on Black NISBET, I. C. T. 2002. Common Tern (Sterna hirundo). Terns provided by the National Audubon Society's The Birds of North America, no. 618. Seabird Restoration Program, the University of New SCHUMMER,M.L.AND W. R. EDDLEMAN. 2003. Effects Brunswick, and I. C. T. Nisbet. S. McBurney willingly of disturbance on activity and energy budgets of performed necropsies. Observations and preparation of migrating waterbirds in south-central Oklahoma. this manuscript were conducted during SRC's graduate Journal of Wildlife Management 67:789±795. studies of Red-breasted Mergansers (Mergus serrator) SIROIS,J.AND M. A. FOURNIER. 1993. Clari®cation of supported by Bishop's University, the Canadian Wild- the status of the Black Tern (Chlidonias niger)in life Federation, the New Brunswick Wildlife Trust the Northwest Territories, Canada. Colonial Wa- Fund, and the Province of QueÂbec Society for the Pro- terbirds 16:208±212. tection of Birds. We thank M.-A. Hudson and three SNOW,D.W.AND C. M. PERRINS. 1998. Black Tern anonymous reviewers for helpful comments on this (Chlidonias niger). Pages 796±799 in The birds of manuscript. the Western Palearctic, vol. 1. Oxford University Press, Oxford, United Kingdom. LITERATURE CITED STEWART,R.E.AND H. A. KANTRUD. 1984. Ecological distribution and crude density of breeding birds BEACH,H.(ED.). 1988. The resources of Kouchiboug- on prairie wetlands. Journal of Wildlife Manage- uac National Park: resource description and anal- ment 48:426±437. SHORT COMMUNICATIONS 107

The Wilson Journal of Ornithology 118(1):107±108, 2006

First Observation of Cavity Nesting by a Female Blue Grosbeak

Thomas S. Risch1,3 and Thomas J. Robinson1,2

ABSTRACT.ÐOn 21 May 2003, we discovered a tures and fallow ®elds, with some nest boxes completed Blue Grosbeak (Passerina caerulea) nest in located along mixed-hardwood forest edge. an Eastern Bluebird (Sialia sialis) nest box. On 28 We checked all nest boxes at least once per May, the nest contained four whitish-tan eggs with light-brown, streaky and spotty markings, an unusual week to monitor nesting activity. On 21 May color pattern for Blue Grosbeak eggs. Species' iden- 2003, we discovered an unidenti®ed, but com- ti®cation was con®rmed by capturing the breeding fe- plete, nest without eggs in a nest box in an male in the nest box, and con®rmed again later with area of open woodland dominated by northern identi®cation of the chicks as Blue Grosbeaks. To our red oak (Quercus rubra) and bordered on one knowledge, this is the ®rst published account of cavity side by a thin stand of privet (Ligustrum spp.). nesting, arti®cial or otherwise, for this species. Re- ceived 27 September 2004, accepted 31 May 2005. The nest was an open cup composed of grass, ®ne sticks, and several interwoven pieces of cellophane. Cellophane is commonly incor- porated within nests of Blue Grosbeaks (In- The Blue Grosbeak (Passerina caerulea)is gold 1993), possibly as a substitute for shed a large bunting in the family Cardinalidae and snakeskin, a common item in grosbeak nests is relatively common in the southeastern Unit- (Strecker 1926). It is unclear why snakeskins ed States. However, little is known of the are incorporated into grosbeak nests (Ingold breeding ecology of this species (Ingold 1993), but their addition to nest boxes with 1993). The nest is typically cup-shaped and arti®cial nests may decrease predation (E. C. composed of twigs, rootlets, and bark, is often Medlin and TSR unpubl. data). This behavior lined with grass and/or ®ne hair, and some- is common in some obligate cavity-nesting times contains arti®cial debris, such as card- species, including Tufted Titmouse (Baeolo- board, cellophane, or newspaper (Stabler phus bicolor) and Great Crested Flycatcher 1959, Bent 1968, Ingold 1993). Blue Gros- (Myiarchus crinitus). We did not measure the beaks commonly build their nests in riparian nest, but the nesting material entirely covered thickets, fallow ®elds, open woodlands, and the ¯oor of the nest box (10 cm wide ϫ 15 hedgerows, usually from 1 to 4 m above the cm deep), and the nest cup covered the rear ground (Stabler 1959, Bent 1968, Ehrlich et 70% of the nest-box ¯oor. We estimated the al. 1988). inside diameter of the nest cup to be ϳ6±7 Here, we detail an observation of cavity cm, which is similar to grosbeak nest-cup di- nesting by a pair of Blue Grosbeaks. We dis- ameters reported by others (Ingold 1993). covered the nest during an ongoing study of On 28 May, we checked the nest again and Eastern Bluebirds (Sialia sialis) in Craighead it contained four oval eggs with light-brown, County, Arkansas. During the winter of 2002, streaky and spotty markings, and a light, whit- we erected approximately 200 Eastern Blue- ish-tan background color. Although Blue bird nest boxes at 2 m above ground, with Grosbeak eggs are typically light blue to white each box being at least 100 m from adjacent and unmarked (Ingold 1993), some are lightly boxes. The site is composed mostly of pas- spotted with brown (Ingold 1993) or ``dis- tinctly marked with dots and spots of chestnut 1 Dept. of Biological Sciences, Arkansas State and subdued lilac'' (Davie 1898:404). The Univ., P.O. Box 599, State University, AR 72467, size, color, and markings of the eggs we ob- USA. served were similar to those of Brown-headed 2 Current address: Dept. of Biological Sciences, 331 Funchess Hall, Auburn Univ., Auburn, AL 36849, Cowbirds (Molothrus ater), so much so that USA. we could not distinguish them from cowbird 3 Corresponding author; e-mail: [email protected] eggs. Although Blue Grosbeaks are frequent 108 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006 hosts of Brown-headed Cowbirds, and cow- nesting occasionally occurs in this species; the birds are known to parasitize hosts nesting in behavior may merit closer examination. nest boxes (Whitehead et al. 2000, 2002), we did not observe nest parasitism in any of our ACKNOWLEDGMENTS nest boxes during our 2-year study. We extend our thanks to J. C. Bednarz, H. B. Fok- Prior to the discovery of the nest, we had idis, J. L. Ingold, M. A. Whitehead, and an anonymous reviewer for comments on previous versions of this observed a pair of Blue Grosbeaks near the manuscript. Additionally, we appreciate J. Cassady and nest box several times over a 2-week period. C. Robertson for their invaluable assistance in the We suspected that the pair was nesting nearby, ®eld. This research was funded by an ASU Faculty but not in the nest box. On 8 June, however, Improvement Grant to TSR in 2003 and 2004, an Ar- we captured a female Blue Grosbeak in the kansas Audubon Society grant to TJR in 2003 and nest box by using a nest-box trap (Robinson 2004; TSR further bene®ted from reassignment time from the Environmental Sciences Program at ASU. et al. 2004); she was incubating the four eggs described above, which appeared to be pip- LITERATURE CITED ping. When we revisited the nest again on 13 BAICICH,P.J.AND C. J. O. HARRISON. 1997. A guide June, we found four nestlings approximately to the nests, eggs, and nestlings of North Ameri- 5 days old and apparently in good condition. can birds, 2nd ed. Academic Press, San Diego, We identi®ed the nestlings as Blue Grosbeaks California. (and not cowbirds) by virtue of their large BENT, A. C. 1968. Eastern Blue Grosbeak. Pages 67± 75 in Life histories of North American cardinals, conical bills and yellow rictal ¯anges. Al- grosbeaks, towhees, ®nches, sparrows, and allies though Brown-headed Cowbirds also have (part 1) (O. L. Austin, Jr., Ed.). U.S. National Mu- conical bills, grosbeaks' bills are obviously seum Bulletin, no. 237, part 1. [Reprinted 1968, larger. In addition, Blue Grosbeak chicks have Dover Publications, New York.] yellow rictal ¯anges (Baicich and Harrison DAVIE, O. 1898. Nests and eggs of North American birds. Landon Press, Columbus, Ohio. 1997), whereas those of Brown-headed Cow- EHRLICH, P. R., D. S. DOBKIN, AND D. WHEYE. 1988. bird chicks are cream-colored in the eastern Blue Grosbeak. Page 556 in The birder's hand- subspecies (Baicich and Harrison 1997). book: a ®eld guide to the natural history of North On 27 June, the nestlings were no longer in American birds. Simon and Schuster, New York. the nest. We assumed they ¯edged success- INGOLD, J. L. 1993. Blue Grosbeak (Guiraca caerulea). fully because there were no obvious signs of The Birds of North America, no. 79. ROBINSON, T. J., L. M. SIEFFERMAN, AND T. S. RISCH. nest predation, and predation at our ®eld site 2004. A quick, inexpensive trap for use with nest is generally low (13% Eastern Bluebird nest boxes. North American Bird Bander 29:115±116. predation; TJR and TSR unpubl. data). STABLER, R. M. 1959. Nesting of the Blue Grosbeak Our observation of Blue Grosbeaks nesting in Colorado. Condor 61:46±48. in a nest box is unique for two reasons: (1) to STRECKER, J. K. 1926. On the use, by birds, of snakes' sloughs as nesting material. Auk 43:501±507. our knowledge, this is the ®rst record of cavity WHITEHEAD, M. A., S. H. SCHWEITZER, AND W. P OST. nesting by Blue Grosbeaks, and (2) the color 2000. Impact of brood parasitism on nest survival pattern of the eggs was unusual. We know of parameters and seasonal fecundity of six songbird few previously published reports of female species in southeastern old-®eld habitat. Condor Blue Grosbeaks laying eggs with brown spot- 102:946±950. WHITEHEAD, M. A., S. H. SCHWEITZER, AND W. P OST. ty markingsÐa rare color pattern for Blue 2002. Cowbird host interactions in a southeastern Grosbeak eggs (Davie 1898, Ingold 1993). old-®eld: a recent contact area? Journal of Field Avian ecologists should be aware that cavity Ornithology 73:379±386. SHORT COMMUNICATIONS 109

The Wilson Journal of Ornithology 118(1):109±112, 2006

A New Record of the Endangered White-winged (Eleothreptus candicans) from Beni, Bolivia

TomaÂsÏ Grim1,3 and Radim SÏumbera2

ABSTRACT.ÐThe ecology of the White-winged in southern Brazil and eastern Paraguay: Emas Nightjar (Eleothreptus candicans) is poorly known. National Park, Brazil (Rodrigues et al. 1999); Only three breeding populations (one from Brazil and AguaraÂNÄ u, Mbaracayu Forest Nature Re- two from Paraguay) are known, and populations are decreasing due to continuing destruction of cerrado serve, Paraguay (Lowen et al. 1996, Clay et habitat. On 14 September 2003, we took several pho- al. 1998); and a recently discovered popula- tos of an unidenti®ed nightjar in Beni Biosphere Re- tion at Laguna Blanca, Departmento San Pe- serve, Departmento Beni, Bolivia. The bird was later dro, central Paraguay (Anonymous 2002). Ad- determined to be an adult male White-winged Nightjar. ditionally, in 1987 a single male was captured Interestingly, the only previous record for Bolivia was and collected at the Beni Biological Station, a male collected in 1987 at the same locality and time of year. Because the White-winged Nightjar is non- Departmento Beni, Bolivia (Davis and Flores migratory and secretive, we hypothesize that there may 1994). Despite speci®c searches for the spe- be a sustainable population of White-winged cies in subsequent years, however, it has not in Bolivia, and the paucity of sightings may be due to been relocated at Beni (Brace et al. 1997, the species' low detectability. Received 16 December Brace 2000, Pople 2004; R. Brace and J. 2004, accepted 11 October 2005. Hornbuckle in litt.). Surveys in AguaraÂNÄ u have resulted in a population estimate of 40±150 individuals The White-winged Nightjar (Eleothreptus (Clay et al. 1998, Pople 2003) at that location. candicans), a member of the Caprimulgidae The number of birds observed in Emas Na- (Cleere 1999, Pople 2004), was recently re- tional Park was 12 in September 1985 and classi®ed from the genus Caprimulgus to the only 1 in October 1990 and in November genus Eleothreptus (Cleere 2002). Its known 1997 (Rodrigues et al. 1999). Although there range and population size are very small, and are no other recently published records from its ecology has received attention only re- Emas, the national park probably supports a cently (Pople 2003). Parker et al. (1996) as- sizeable population of E. candicans (Pople signed the species High Conservation Priority 2004) because Emas encompasses a large ex- and the IUCN lists the species as Endangered tent of apparently suitable habitat. The re- (IUCN Red List; Pople 2004). E. candicans is cently discovered population at Laguna Blan- threatened by ongoing loss of its cerrado hab- ca in Paraguay is estimated to include a min- itat (heavy grazing, trampling, invasive grass- imum of 30 birds (R. P. Clay in litt.). es, habitat conversion to plantations, and On 14 September 2003 at 22:00 EDT, we large-scale, uncontrolled grass ®res; Cleere photographed an unidenti®ed nightjar on a ter- 1999, Pople 2004). mite mound between the Beni Biological Sta- Until the 1980s, White-winged Nightjars tion (EstacioÂn BioloÂgica del Beni; 14Њ 50Ј S, were known only from two museum speci- 66Њ 17Ј W) and Laguna Normandia (ϳ1.5 km mens collected at the beginning of the 19th northwest of the station; see Fig. 3 in Brace century in OricËanga, SaÄo Paulo state, and Cu- et al. 1997), Departmento Beni in northern iabaÂ, Mato Grosso state, Brazil (Sclater 1866). Bolivia. Later the bird was unambiguously Only three populations have been found, all identi®ed as a male E. candicans (Fig. 1). Be- cause it lacked visible wear on the remiges 1 Dept. of Zoology, Palacky Univ., Tr. Svobody 26, and pale ¯ecking in the contour plumage, it is 771 46 Olomouc, Czech Republic. 2 Dept. of Zoology, Univ. of South Bohemia, Bran- probable that the individual had recently com- isÏovska 31, 37005 Ceske Budejovice, Czech Republic. pleted a molt. If the species undergoes the 3 Corresponding author; e-mail: [email protected] same pattern of molt in both Beni Biosphere 110 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006

FIG. 1. Adult male White-winged Nightjar (Eleothreptus candicans) photographed on 14 September 2003 in Beni Biosphere Reserve, Departmento Beni, Bolivia. Photo by R. SÏumbera.

Reserve and Paraguay (i.e., replacement of buckle (in litt.), for example, searched for ¯ight in a single post-nuptial molt), it White-winged Nightjars and conducted mist- suggests that the species may breed consid- netting from mid-July through the end of Au- erably earlier in Bolivia than in Paraguay gust every year from 1992 to 1999, but re- (where it breeds mainly between September corded no White-winged Nightjars. Although and December). the White-winged Nightjar is considerably Beni Biological Station is 180 km west of less conspicuous than many other sympatric Trinidad and 50 km east of San Borja on El nightjar species common in Bolivia (R. G. Po- Porvenir EÂ stancia. El Porvenir EÂ stancia lies in ple in litt.), it seems unlikely that there would the Llanos de Mojos, which is a lowland plain be so few observations of the species if the (ϳ200 m elevation) characterized as savanna area supported a small resident population. with forest islands. The habitat where we ob- Rather, the two individuals recorded during served the White-winged Nightjar is a season- the last 2 decades may have come from an ally inundated savanna with a high density of undiscovered population elsewhere in the termite mounds (Fig. 2). northern Bolivian lowlands. However, E. can- Ours is only the second record of White- dicans is presumed to be a resident species. winged Nightjar in Bolivia, the ®rst having Indeed, radio-tracking work in Paraguay (Po- been made in September 1987 (Davis and Flo- ple 2003) revealed that White-winged Night- res 1994). Interestingly, both observations jars are year-round residents, and a study of were made near Beni Biological Station at the captive birds revealed a post-nuptial molt pat- same time of year (11 September 1987 and 14 tern typical of a nonmigratory species. There- September 2003). Despite a number of re- fore, the occurrence of the two individuals at search programs that have been conducted at Beni Biological Station during the same time the station (A. B. Hennessey in litt.), there had of year may indicate that some birds make been no additional records of White-winged local movements, possibly in response to ®res Nightjar after 1987. R. C. Brace and J. Horn- (Pople 2004). SHORT COMMUNICATIONS 111

FIG. 2. Typical habitat of the White-winged NightjarÐwet savanna with termite mounds providing perches above the surrounding young vegetation. The forest in the background is Florida Fragment south of Laguna Normandia, 1.5 km northwest of Beni Biological Station, Departmento Beni, Bolivia. The photo in Figure 1 was taken within this area. Photo by T. Grim.

Neotropical savannas are under increasing serve (Brace et al. 1997, Brace 2000). We add human pressure due to large-scale conversion to this list one more species: on the same day of grassland habitats to pastures (Marris (14 September 2003) that we observed the 2005). Although the White-winged Nightjar is White-winged Nightjar, we also recorded one a typical savanna dweller and is adapted to Black-throated Saltator (Saltator atricollis). irregular and small-scale ®res, it likely has We hypothesize that Departmento Beni in been negatively affected by regular and large- northern Bolivia holds a resident population scale burning in recent years (Brace et al. of E. candicans, and that the paucity of re- 1997, Pople 2004). Conservation of savanna cords from Bolivia re¯ects the lack of inten- habitatsÐincluding cerrado, the primary hab- sive searches during the correct season and the itat for E. candicansÐhas been neglected thus low detectability of this species. We concur far. Because savanna habitats are facing great- with Brace et al. (1997) that more information er threats than Amazonian rainforests, the on the White-winged Nightjar's status is re- conservation of cerrado habitat should be- quired, and we hope that our observation pro- come a top priority in the Neotropics (Marris vides an impetus for further research on this 2005). elusive species. Our observation highlights the importance of Beni Biosphere Reserve for threatened (n ACKNOWLEDGMENTS ϭ 4) and near-threatened (n ϭ 15) bird species in Bolivia (Brace et al. 1997). Among these We are grateful for the detailed and helpful com- ments and suggestions by R. P. Clay and two anony- 19 species are 11 that rely wholly or partially mous referees. We thank R. C. Brace and A. B. Hen- on savanna habitat. So far, 500 bird species nessey for their comments on the manuscript and G. have been reported from Beni Biosphere Re- Dryden for reviewing our translation to English. 112 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006

LITERATURE CITED LOWEN, J. C., L. BARTRINA,T.M.BROOKS,R.P.CLAY, AND J. TOBIAS. 1996. Project YACUTINGA '95: ANONYMOUS. 2002. A new population of the White- bird surveys and conservation priorities in eastern winged Nightjar. World Birdwatch 24:5. Paraguay. Cotinga 5:14±19. RACE B , R. C. 2000. The avifauna of the Beni Biolog- MARRIS, E. 2005. The forgotten ecosystem. Nature ical Station: records to 1999. EstacioÂn Biologica 437:943±944. del Beni, Bolivia. PARKER, T. A., III, D. F. STOTZ, AND J. W. FITZPATRICK. BRACE, R. C., J. HORNBUCKLE, AND J. W. PEARCE-HIG- 1996. Ecological and distributional databases for GINS. 1997. The avifauna of the Beni Biological Neotropical birds. Pages 118±407 in Neotropical Station, Bolivia. Bird Conservation International birds: ecology and conservation (D. F. Stotz, J. W. 7:117±159. Fitzpatrick, T. A. Parker, III, and D. K. Moskov- CLAY, R. P., D. R. CAPPER,J.MAZAR BARNETT,I.J. its). University of Chicago Press, Chicago, Illi- BURFIELD,E.Z.ESQUIVEL,R.FARINÄ A,C.P.KEN- nois. NEDY,M.PERRENS, AND R. G. POPLE. 1998. White- POPLE, R. G. 2003. The ecology and conservation of winged Nightjars Caprimulgus candicans and cer- the White-winged Nightjar Caprimulgus candi- rado conservation: the key ®ndings of Project AguaraÂNÄ u 1997. Cotinga 9:52±56. cans. Ph.D. dissertation, University of Cambridge, United Kingdom. CLEERE, N. 1999. Family Caprimulgidae (nightjars). Pages 302±386 in Handbook of the birds of the POPLE, R. G. 2004. White-winged Nightjar Eleothrep- world, vol. 5: barn-owls to hummingbirds (J. del tus candicans. In Threatened birds of the world Hoyo, A. Elliott, and J. Sargatal, Eds.). Lynx Ed- 2004. CD-ROM. BirdLife International, Cam- icions, Barcelona, Spain. bridge, United Kingdom. CLEERE, N. 2002. A review of the taxonomy and sys- RODRIGUES, F. H. G., A. HASS,O.J.MARINI-FILHO,M. tematics of the Sickle-winged and White-winged M. GUIMARAÄ ES, AND M. A. BAGNO. 1999. A new nightjars (Caprimulgidae). The Bulletin of the record of White-winged Nightjar Caprimulgus British Ornithologists' Club 122:168±179. candicans in Emas National Park, GoiaÂs, Brazil. DAVIS,S.E.AND E. FLORES. 1994. First record of Cotinga 11:83±85. White-winged Nightjar Caprimulgus candicans SCLATER, P. L. 1866. Additional notes on the Capri- for Bolivia. The Bulletin of the British Ornithol- mulgidae. Proceedings of the Zoological Society ogists' Club 114:127±128. of London 1866:581±590.

The Wilson Journal of Ornithology 118(1):112±113, 2006

Predation of Eared Grebe by Great Blue Heron

James W. Rivers1,2 and Michael J. Kuehn1

ABSTRACT.ÐGreat Blue Herons (Ardea herodias) On the morning of 14 November 2004, we typically prey upon ®sh and other aquatic organisms, witnessed an adult Great Blue Heron (Ardea and they occasionally take small mammals and birds. herodias) attack, kill, and attempt to consume We observed a Great Blue Heron attack, kill, and at- tempt to consume an Eared Grebe (Podiceps nigricol- an Eared Grebe (Podiceps nigricollis) at Oso lis). The heron was unable to swallow the grebe, and Flaco Lake (35Њ 00Ј N, 120Њ 30Ј W) in San it abandoned the carcass after approximately 30 min. Luis Obispo County, California. The incident An examination of the carcass showed that the grebe occurred shortly after the heron landed near lacked obvious physical deformities. Our observation, the grebe and began foraging in shallow (ϳ30 coupled with a similar one nearby, indicates that Great cm deep) water. At approximately 11:25 PST, Blue Herons attack and kill birds larger than reported previously. Received 11 January 2005, accepted 19 the heron caught the grebe with a stabbing September 2005. motion as the grebe swam underwater. The heron then proceeded to subdue the grebe by grasping its neck, shaking it, and submerging it intermittently. After approximately 15 min, 1 Dept. of Ecology, Evolution, and Marine Biology, Univ. of California, Santa Barbara, CA 93106, USA. the grebe appeared to be dead. At this point, 2 Corresponding author; e-mail: the heron brie¯y released the grebe to deliver [email protected] several sharp blows to its head and chest area. SHORT COMMUNICATIONS 113

The heron attempted several times to swal- Butler pers. comm.). Thus, it is possible that low the grebe, but it had dif®culty maneuver- the herons may have targeted the grebes as ing the grebe into its mouth. During one at- potential prey items, but were unable to suc- tempt, it was able to maneuver the carcass into cessfully consume them because of their size. position, but the grebe's diameter, its limp Alternative explanations are (1) that the her- wings, or both prevented the heron from swal- ons mistook the grebes for ®sh or (2) that the lowing it. After attempting to swallow the herons were acting to defend a foraging area. grebe for approximately 15 min, the heron Indeed, an observer at Lake Cachuma report- abandoned the carcass, preened brie¯y, and ed seeing a foraging heron attack and kill an then ¯ew off. The grebe weighed 255 g American Coot (Fulica americana) with no (weighed after the grebe was frozen and then attempt to eat it (L. R. Mason pers. comm.). thawed), and although that is low body weight The heron we observed, however, expended a for this species (Cullen et al. 1999), it is typ- substantial amount of effort subduing and at- ical of grebes arriving on a wintering area af- tempting to consume the grebe, indicating a ter a migratory ¯ight (Jehl 1997; J. R. Jehl, deliberate act of predation. Evidently, small Jr. pers. comm.). When we examined the grebes are potential prey items for Great Blue grebe, we found no deformities or obvious in- Herons, and herons may attack and kill large dications of poor condition (e.g., loss of pec- birds more commonly than is recognized. toral muscle). On the day previous to our observation (13 ACKNOWLEDGMENTS November 2004), H. R. Pedersen (pers. We thank K. E. Jirik, the students of the Terrestrial comm.) observed a Great Blue Heron at Lake Vertebrate Ecology Laboratory course at the Univer- Cachuma in Santa Barbara County, California sity of California-Santa Barbara, and members of the (ϳ130 km southeast of Lake Oso Flaco), cap- Pomona Valley and Golden Gate Audubon Societies ture an Eared Grebe. The heron was foraging for their assistance with observations. H. R. Pedersen and caught the grebe in shallow water, grasped and L. R. Mason kindly shared their observations of it by the neck in the same manner we wit- foraging herons; R. W. Butler provided helpful discus- sion; and J. R. Jehl, N. V. McCanch, and an anony- nessed, and submerged it several times. After mous reviewer provided valuable comments on the a brief struggle, the grebe escaped and ap- manuscript. peared unharmed (H. R. Pedersen pers. comm.). LITERATURE CITED We know of no previous reports of Great Blue Herons capturing, killing, and attempting BUTLER, R. W. 1992. Great Blue Heron (Ardea hero- to consume Eared Grebes, or any other bird dias). The Birds of North America, no. 25. CULLEN, S. A., J. R. JEHL,JR., AND G. L. NUECHTER- species of that size; however, McCanch LEIN. 1999. Eared Grebe (Podiceps nigricollis). (2003) reported a Grey Heron (Ardea cinerea) The Birds of North America, no. 433. that had choked to death while attempting to JEHL, J. R., JR. 1997. Cyclical changes in body com- ingest a Little Grebe (Tachybaptus ru®collis). position in the annual cycle and migration of the Great Blue Herons have a diverse diet that Eared Grebe Podiceps nigricollis. Journal of Avi- includes songbirds and mammals of various an Biology 28:132±142. MCCANCH, N. 2003. Grey Heron choking on Little sizes (Peifer 1979, Butler 1992), and they Grebe. British Birds 96:86. have been observed abandoning large prey PEIFER, R. W. 1979. Great Blue Herons foraging for items that they were unable to swallow (R. W. small mammals. Wilson Bulletin 91:630±631. 114 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006

The Wilson Journal of Ornithology 118(1):114±116, 2006

Abnormal Eggs and Incubation Behavior in Northern Bobwhite

Fidel HernaÂndez,1,2 Juan A. Arredondo,1 FroylaÂn HernaÂndez,1 Fred C. Bryant,1 and Leonard A. Brennan1

ABSTRACT.ÐA long-term (Ͼ5 years) study of (e.g., Canada Goose, Branta canadensis Northern Bobwhite (Colinus virginianus) provided the [Manning and Carter 1977]; woodpeckers [Pi- ®rst record of runt eggs and two observations of pro- cidae, Koenig 1980b]; and Eastern Bluebird, longed incubation. During 2004, we located two clutches (n ϭ 11 and 9 eggs)Ðlaid by the same henÐ Sialia sialis [Mulvihill 1987]), they normally consisting entirely of runt eggs. Mean length, width, occur at low frequencies (ϳ1 per 1,000 to and mass were 18.8 mm, 15.4 mm, and 2.0 g, respec- 2,000 eggs; Koenig 1980b, Mallory et al. tively, 26% of the volume and 24% of the mass of 2004). Furthermore, runt eggs usually repre- typical bobwhite eggs. Based on our long-term data sent only a small proportion of a clutch (Roth- ϭ set for bobwhites (n 3,566 eggs), runt eggs occur at stein 1973, Ricklefs 1975, Bartel 1986). Entire a frequency of 0.56%, within the range (0.02±4.32%) reported for other avian species. The two records of clutches consisting solely of runt eggs are ex- prolonged incubation behavior represented 75 days tremely rare and have been reported only for (326%) and 47 days (204%) beyond the normal incu- Song Thrush (Turdus philomelos; M'William bation period (23 days) of bobwhites. This prolonged 1927), Gray Catbird (Dumetella carolinensis; incubation behavior is in excess of the time frame re- Rothstein 1973), and Eastern Bluebird (Ze- ported for most birds exhibiting prolonged incubation leny 1983). We report the ®rst record of runt (50±100% beyond normal incubation). Received 31 eggs for Northern Bobwhite and provide es- January 2005, accepted 3 October 2005. timates of the frequency of such eggs. On 21 June 2004, we located a radiomarked hen on a nest at the base of brownseed pas- Documenting anomalies in avian behavior palum (Paspalum plicatulum). The clutch often is an opportunistic endeavor given the consisted entirely of runt eggs (n ϭ 11). We rarity of such behavior and the short-term na- monitored the hen for several days thereafter, ture (Ͻ2 years) of most studies. An ongoing, but never located her at the nest site again. long-term (Ͼ5 years) radiotelemetry project We concluded that she had abandoned the nest (The South Texas Quail Research Project; and we collected the eggs. During the follow- STxQRP) on Northern Bobwhite (Colinus vir- ing 5 weeks, the hen again paired with a male, ginianus) provided us with the opportunity to and on 30 July, we documented a second monitor bobwhite behavior over seven breed- ϭ ing seasons (1998±2004) on the Encino Di- clutch of runt eggs (n 9) in a nest con- vision of the King Ranch, Inc., Brooks Coun- structed in red lovegrass (Eragrostis secun- ty, Texas. We provide the ®rst record of runt di¯ora). The hen also abandoned this nest, and eggs for Northern Bobwhite and two addition- we collected the clutch on 2 August. al records of prolonged incubation behavior. None of the runt eggs was viable (i.e., none First record of runt eggs.ÐRunt eggs, also contained yolk). Mean length, width, and ϭ referred to as dwarf, cock, wind, and witch mass of the runt eggs (n 20) were 18.8 mm, eggs (Rothstein 1973), are those noticeably 15.4 mm, and 2.0 g, respectively. The smallest smaller than the smallest expected for a given reported measurements for bobwhite eggs are species (Mulvihill 1987; for suggested crite- 26 mm (length) and 22.5 mm (width) (Bent ria, see Koenig 1980a). Although runt eggs 1932), and 8.2 g (Case and Robel 1974). Koe- have been reported for several avian species nig (1980a) de®ned runt eggs as those with a relative volume (length ϫ width2 ϫ␲/6) Ͻ75% of the average. Mean length, width, 1 Caesar Kleberg Wildlife Research Inst., Texas A&M Univ., Kingsville, TX 78363, USA. and mass of bobwhite eggs are 30 mm, 24 2 Corresponding author; e-mail: mm, and 8.3 g, respectively (Bent 1932, Case ®[email protected] and Robel 1974). Thus, the volume and mass SHORT COMMUNICATIONS 115 of the runt eggs we found were only 26% and observed on the nest between 9 and 25 Sep- 24%, respectively, of the average. tember, but on 26 September, the hen returned We used data from STxQRP and HernaÂndez to the nest and resumed incubation until 5 De- (1999) to estimate the frequency of runt eggs cember. Thus, the hen incubated the eggs for in Northern Bobwhite. During 1999±2004 of 28 days, abandoned the nest for 17 days, and the STxQRP, we located 392 nests and deter- then resumed incubation for another 70 days. mined clutch size for 297 nests (n ϭ 3,161 The 98 days of incubation was 75 days eggs). HernaÂndez (1999) located 83 bobwhite (326%) beyond the normal incubation period nests in Shackelford County, Texas during for bobwhites. 1997±1998 and determined clutch size for 35 We documented the second occurrence of nests (n ϭ 385 eggs). Based on these com- prolonged incubation during the 2004 nesting bined data (3,546 normal-sized eggs ϩ 20 runt season. On 18 June, we accidentally ¯ushed eggs), runt eggs in bobwhites occur at a fre- an un-radiomarked hen from a nest. We re- quency of 0.56%, which is within the range turned to the nest site on 12 July, presuming (0.02±4.32%) reported for other avian species the clutch had hatched, and found her still in- (Koenig 1980b, Mallory et al. 2004). cubating the clutch. The hen continued incu- The mechanisms underlying the production bating until 27 August, when the clutch was of runt eggs are not entirely understood (Mul- depredated. Assuming the hen had just begun vihill 1987). However, runt eggs often are pro- incubation when we ®rst found the nest, she duced after temporary disturbance or damage incubated for at least 70 days, or 47 days (e.g., injury or infection) to the reproductive (204%) beyond the normal incubation period organs (Pearl and Curtis 1916, Romanoff and for bobwhites. Romanoff 1949). Instances of entire clutches Although only 1 of 10 eggs hatched in our being composed of runt eggs suggest a con- ®rst observation of prolonged incubation, genital defect or permanent injury to the re- Murray and Frye (1957) suggest that the productive system (Mulvihill 1987). We pre- hatching of even one egg is suf®cient to sat- sume the bobwhite hen that laid the runt eggs isfy the nesting instinct. In our observation, may have suffered from some type of per- however, the hen continued incubation even manent injury to her reproductive organs. though only one egg hatched. Hurst (1978) Prolonged incubation behavior.ÐPro- observed a similar phenomenon, during which longed incubation beyond the normal time re- a bobwhite hen continued incubation of par- quired for hatching has been reported for tially hatched, dead chicks. The clutch con- many avian species, including Killdeer (Cha- sisted of 10 eggs: 1 infertile, 1 completely radrius vociferus; Powers 1978), Common hatched, and 8 partially hatched. The eight Loon (Gavia immer; Sutcliffe 1982), and partially hatched eggs contained fully devel- Long-eared Owl (Asio otus; Marks 1983). oped chicks that had pipped and partially Most birds that exhibit prolonged incubation ringed their eggshells but had become ``en- appear to incubate for at least 50±100% lon- tombed.'' Hurst (1978) did not report the ger than necessary to hatch a clutch (Skutch length of time that the hen remained on the 1962). Prolonged incubation (56 days) has partially hatched eggs. been reported only once for Northern Bob- Prolonged incubation is thought to provide white (Stoddard 1931), which is 33 days a safety margin for eggs that take longer than (143%) beyond the average incubation period normal to hatch (Skutch 1962, Holcomb (23 days). We report two additional records of 1970). However, Holcomb (1970) suggested prolonged incubation for Northern Bobwhite. that prolonged incubation would be maladap- During our ®rst observation of prolonged tive for species capable of renesting. Bob- incubation, a bobwhite hen exhibited normal whites commonly renest two or three times incubation behavior during a ®rst nesting, and per breeding season, regardless of previous the eggs successfully hatched on 7 July 2003. nest fate (Stoddard 1931). Given that the two However, the hen exhibited prolonged incu- records of prolonged incubation occurred to- bation of a second clutch. We discovered the ward the end (July±August) of the normal nest on 11 August, and by 8 September, only nesting season for bobwhites (May±August), 1 of 10 eggs had hatched. The female was not the opportunity for renesting was limited and 116 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 118, No. 1, March 2006 may have contributed to prolonged incuba- KOENIG, W. D. 1980a. The determination of runt eggs tion. in birds. Wilson Bulletin 92:103±107. KOENIG, W. D. 1980b. The incidence of runt eggs in woodpeckers. Wilson Bulletin 92:169±176. ACKNOWLEDGMENTS MALLORY, M. L., L. KIFF,R.G.CLARK,T.BOWMAN, This research was supported by the George and P. B LUMS,A.MEDNIS, AND R. T. ALISAUSKAS. Mary Josephine Hamman Foundation; Amy Shelton 2004. The occurrence of runt eggs in waterfowl McNutt Charitable Trust; William A. and Madeline clutches. Journal of Field Ornithology 75:209± Welder Smith Foundation; Bob and Vivian Smith 217. Foundation; Robert J. Kleberg, Jr., and Helen C. Kle- MANNING,T.H.AND B. CARTER. 1977. Incidence of berg Foundation; Texas State Council of Quail Unlim- runt eggs in the Canada Goose and Semipalmated ited; the South Texas, Houston, East Texas, and Alamo Sandpiper. Wilson Bulletin 89:469. Chapters of Quail Unlimited; the South Texas Celeb- MARKS, J. S. 1983. Prolonged incubation by a Long- rity Weekend; Quail Associates; private contributions; eared Owl. Journal of Field Ornithology 54:199± King Ranch, Inc.; and San Tomas Hunting Camp. We 200. MULVIHILL, R. S. 1987. Runt eggs: a discovery, a syn- thank B. M. Ballard, D. G. Hewitt, and three anony- opsis, and a proposal for future study. North mous reviewers for providing helpful comments on an American Bird Bander 12:94±96. earlier version of this manuscript. Data for this re- MURRAY,R.W.AND O. E. FRYE,JR. 1957. The Bob- search were provided by the South Texas Quail Re- white quail and its management in Florida. Game search Project. This manuscript is Caesar Kleberg Publication 2, Florida Game and Fresh Water Wildlife Research Institute Publication Number 05- Commission, Tallahassee, Florida. 112. M'WILLIAM, J. M. 1927. Some abnormal eggs of wild birds. Scottish Naturalist 66:108±110. LITERATURE CITED PEARL,R.AND M. R. CURTIS. 1916. Studies on the physiology of reproduction in the domestic BARTEL, K. E. 1986. Another record of runt eggs for fowlÐXV. Dwarf eggs. Journal of Agricultural the Tree Swallow. North American Bird Bander Research 6:977±1042. 11:3±4. POWERS, L. R. 1978. Record of prolonged incubation BENT, A. C. 1932. Eastern, Florida, and Texas Bob- by a Killdeer. Auk 95:428. white. Pages 9±36 in Life histories of North RICKLEFS, R. E. 1975. Dwarf eggs laid by a starling. American gallinaceous birds. U.S. National Mu- Bird Banding 46:169. seum Bulletin, no. 162. [Reprinted 1963, Dover ROMANOFF,A.L.AND A. J. ROMANOFF. 1949. The avi- Publications, New York.] an egg. John Wiley and Sons, New York. CASE,R.M.AND R. J. ROBEL. 1974. Bioenergetics of ROTHSTEIN, S. I. 1973. The occurrence of unusually the Bobwhite. Journal of Wildlife Management small eggs in three species of songbirds. Wilson 38:638±652. Bulletin 85:340±342. Â HERNANDEZ, F. 1999. The value of prickly pear cactus SKUTCH, A. F. 1962. The constancy of incubation. Wil- as nesting cover for Northern Bobwhite. Ph.D. son Bulletin 74:115±152. dissertation, Texas A&M University, Kingsville STODDARD, H. L. 1931. The Bobwhite quail: its habits, and College Station. preservation and increase. Charles Scribner's HOLCOMB, L. C. 1970. Prolonged incubation behaviour Sons, New York. of Red-winged Blackbird incubating several egg SUTCLIFFE, S. 1982. Prolonged incubation behavior in sizes. Behaviour 36:74±83. Common Loons. Wilson Bulletin 94:361±362. HURST, G. A. 1978. Unusual incubation behavior in ZELENY, L. 1983. Miniature bluebird eggs. Sialia 5: Bobwhite. Wilson Bulletin 90:290±291. 127±128.