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Ontario Gray Jays Help on the World Stage: Part 1

Dan Strickland

Readers of Ontario Birds may not suggest how our Gray Jay perspec­ be generally aware of the phenom­ tive may be extended to help enon of "helping" in birds. Found in explain the absence or presence of over 200 species worldwide and communal breeding around the sometimes called cooperative or world. communal breeding, helping is Communal breeding in birds characterized by more than two was first reported in 1935 by adults participating in parental Alexander F. Skutch, the great activities such as nest building, American naturalist who has spent attacking nest predators, and espe­ over 70 years, mostly in Costa cially the feeding of nestlings. Rica, documenting the lives of Ontario birders are also probably neotropical birds. Skutch described unaware that study of one of our how the nests of three species province's common species, the (Brown Jay Cyanocorax morio, Gray Jay (Perisoreus canadensis), Black-eared Bushtit Psaltriparus may have provided a useful contri­ minimus, and Banded Cactus Wren bution to understanding this behav­ Campylorhynchus zonatus) were iour. In December 2001, Tom Waite regularly attended by more than of Ohio State University and I two adults (Skutch 1935). Because developed this idea in an article the extra birds made numerous published in the Canadian Journal trips to the nest with food for the of Zoology (Strickland and Waite nestlings, Skutch called the extra 2001). I am pleased to present a less birds (and his paper) "Helpers at technical version in this and the fol­ the nest". Unfortunately, the words lowing issue of Ontario Birds which "helper, help, and helping" have I hope will explain our idea to a stuck ever since (see box, "The wider audience. Here, in Part 1, I Name 'Helping' is not Helpful!"). summarize the present thinking Little or no attention was paid about communal breeding (as I to Skutch's discovery for several much prefer to call helping) and decades but, in the 1960s, people describe the challenge to this think­ began to recognize what a paradox ing that the Gray Jay poses. In Part it represented. The intellectual 2, I will discuss the hypothesis we underpinning of biology is evolu­ offer to explain the Gray Jay's puz­ tion through natural selection. That zling social behaviour. I will also is, everything we see in an organ- ONTARIO BIRDS DECEMBER 2002 131

The Name "Helping" is not Helpful! The name "helping" is unfortunate breeding Florida ScrUb-Jays help because it carries an inescapable (i.e., confer benefit) but not when connotation of benefit. It may seem they help (i.e., feed nestlings)". self-evident that nonbreeding birds The way to avoid such confu­ must be doing something positive sion is to define and use clear terms when they direct parent-like behav­ that carry no presumption about iour to another bird's young but, the function of the behaviour they until proven, that idea is only pre­ refer to. Thus, we should never use sumption-not a fact. the terms "cooperative breeding" Even worse is the equally wide­ or "helping" unless we have evi­ spread use of "helping' to designate dence that actual cooperation or the specific act of feeding another benefits are involved. Until then, bird's young. To see why, consider the when we see more than two birds situation in the Florida Scrub-Jay involved in a nesting effort, we (Aphelocoma coerulescens). In this should say "communal breeding". well-known communal breeder, non­ Similarly, we should never assume breeders associate with, and feed the that feeding another bird's nestlings nestlings of, about half of all breeding amounts to "help". Instead, we pairs. Pairs with nonbreeders pro­ should use the term "allofeed" as duce more young than do pairs with­ suggested by one of the leading sci­ out nonbreeders and it may therefore entists in the field, Jerram Brown seem justified to conclude that the (1987). Then we can say-sensibly extra feeders are helping the breed­ this time-that nonbreeding ers when they feed the nestlings. The Florida Scrub-Jays help, but not trouble is that the improved produc­ when they allofeed. And, if it seems tion of young is brought about by the that I am splitting hairs here trust improved nest defence provided by me; as far as Gray Jays are con­ the nonbreeders, not by the food they cerned the old, still entrenched bring. If we were to use "helping" to terms (helping and cooperative designate the feeding of nestlings by breeding) were serious impedi­ nonbreeders, therefore, we would ments to understanding the behav­ logically be able to say that "non- iour of these birds. ism, from its physical make-up to its some heritable property which behaviour, is thought to be the way results in a longer life or greater it is because the feature in question success in mating will, other things results in the greatest survival and being equal, leave more descen­ mating success-and ultimately in dants than its rivals and conse­ the greatest production of surviving quently the beneficial property will young. Any individual that has become more and more widespread VOLUME 20 NUMBER 3 132 in the species with each passing 1970s and 80s, this became one of the generation. Conversely, if an indi­ hottest fields in ornithology and it vidual has some new heritable continues to be one of the most fasci­ physical feature or behaviour that nating to many scientists right up to results in a shorter life and/or less the present. Specific studies have breeding success, the new feature investigated Dunnocks (Prunella will not spread or become estab­ modularis) in Europe; Pied lished in the population. Instead, it Kingfishers (Ceryle rudis), White­ will disappear-quickly weeded out throated Bee-eaters (Merops bul­ by an unconscious "natural selec­ lockoides), and Green Woodhoopoes tion"-just as surely as if, say, a (Phoeniculus purpureus) in Africa; human animal breeder were decid­ Superb Blue Wrens (Malurus cya­ ing which individual dogs or neus), Noisy Miners (Manorina pigeons will be prevented from melanocephala), and Grey-crowned passing on their properties to the Babblers (Pomatostomus temporalis) next generation. in Australia; Hoatzins (Opisthocomus But, given this fundamental hoazin) and Stripe-backed Wrens truth about the evolution of living (Campylorhynchus nuchalis) in organisms, how can we possibly South America; and, closer to home, explain "helping" or communal Florida Scrub-Jays, Mexican Jays breeding in birds? How can individ­ (Aphelocoma ultramarina), Pinyon uals that refrain from breeding pass Jays (Gymnorhinus cyanocephalus), along the genes for such restraint to and Acorn Wood-peckers (Melan­ succeeding generations? How can erpes formicivorus) here in North individuals with a proclivity to forgo America. Although many of the orig­ breeding themselves and instead to inal questions had been partly or "help" the breeding of others possi­ completely solved by the 1990s (see bly persist in a species? Seen in this box, "Why Stay at Home and Feed light, communal breeding was rec­ Young That Aren't Yours?"), there ognized, not as some inconsequen­ still remained a number of unan­ tial side-show of nature, but as a swered questions about communal major challenge to the idea of evo­ breeding. One of these concerned the lution by natural selection-and uneven distribution of communally therefore to the very foundations of breeding birds around the world. It modern biology. was understandable that many would Attracted by the huge implica­ be tropical species because it is in the tions of resolving-or not resolv­ tropics that birds tend to be perma­ ing-such a big question, dozens of nently territorial. Tropical species are ornithologists began detailed, long­ also often at "saturation density" term studies of colour-banded popu­ because their numbers aren't deci­ lations of communally breeding mated once or twice a year in long species on every continent. In the and dangerous migrations. Both of ONTARIO BIRDS DECEMBER 2002 133

Figure 1: Nestling Gray Jays are fed exclusively by their own parents, never by any nonbreeder that may also be on the territory. Photo by Dan Strickland.

Figure 2: A fledgling Gray Jay like this one is sometimes fed by a nonbreeder as well as by its own parents. Photo by Dan Strickland. VOLUME 20 NUMBER 3 134

Why Stay at Home and Feed Young That Aren't Yours? Communal breeding turned out to and Steve Emlen of Cornell be less of a paradox than it first University in Ithaca) have listed at appeared. For one thing, in most least nine hypotheses that may species, allofeeders (i.e., "helpers ) explain how communal breeding were almost never refraining from could be useful in one species or breeding. They had little or no another (Brown 1987, Emlen et al. choice. Usually they were young 1991). Basically, these hypotheses birds still living with their parents are of two types. In the first catego­ because they had been unable to ry, the proposed explanations sug­ find territories of their own. Other gest that the allofeeder benefits times they belonged to species directly from his or her actions. One where only older birds with a great idea for example, is that, by helping deal of experience had any hope of to raise young birds the allofeeder breeding successfully. Either way gains valuable experience that will the young birds had almost no make it a more productive parent chance of breeding themselves. when it becomes a breeder itself. Still, this does nothing to explain Another idea in this category is why the nonbreeders should actual­ exemplified by the Florida Scrub­ ly spend energy feeding young birds Jay (Woolfenden and Fitzpatrick that aren t their own. 1984). In this species, a nonbreeding From various studies, it bird improves its chances of becom­ emerged that there was not just one ing a breeder by helping a breeding possible answer to this important pair to raise more young birds than question. Indeed, the leading theo­ it would otherwise. The consequent­ reticians in the field, both as it hap­ ly enlarged family expands its terri­ pens from just next door to Ontario tory at the expense of smaller (Jerram Brown of the State neighbouring groups and then the University of New York at Albany, nonbreeder "buds off" part of the these factors tend to produce condi­ munally as opposed to only 2 percent tions where young birds can't find elsewhere even including ecological­ vacant territories and are therefore ly apparently similar areas in Africa, forced to stay at home as nonbreed­ Asia, and South America. ers. Still, other features about the Another mystery was why some geographic distribution of communal birds here and there around the breeders were not so obvious. In par­ world lived in family groups but, at ticular such species are especially least in the nestling period, did not abundant in Australia. About 10 per­ exhibit communal breeding. These cent of birds down under breed com- included the Western Scrub-jay (A. o TARIO BIRDS DECEMBER 2002 135

new, bigger territory and claims it as But is this really true? At first his own. The nonbreeder has blush, this may seem like a silly become a breeder, in effect, by question. Surely it is self-evident helping the adults to "raise an that the act of putting food down army" that ends up conquering a the throats of nestlings can only be territory for his use. helpful. Everyone knows how hard The second type of explanation bird parents have to work to find that has been proposed to explain food for their young and a funda­ communal breeding relies on the fact mental prediction of evolutionary that allofeeders are usually still at theory is that birds should lay home with their parents. The clutches that result in the maxi­ allofeeders are, therefore, feeding mum number of healthy, surviving their own younger brothers and sis­ young. Surely, under these circum­ ters. These younger siblings and the stances, the efforts of nonbreeders helpers consequently share half their can only be of benefit. genes. This is the same proportion of Well, not necessarily. Detailed genes that would be shared by an studies in many species have failed to allofeeder and its own offspring if it reveal any improvement in the pro­ had any. In other words by helping to duction of young when allofeeders raise more or healthier siblings, an are present. That is in some species allofeeder is indirectly advancing the unaided parents do just as well as cause of its own genes much the way those supposedly benefiting from the it would be doing directly if it could 'help" of allofeeders. And, as we raise young of its own. shall see in Part 2 there is at least Of course, all of these pro­ one way that allofeeding could be posed explanations rest on the anything but helpful. It could be assumption that "helpers" really do downright harmful. gain and/or confer some benefit. californica) at the southern end of its never feed young (Gayou 1986). range near Oaxaca, Mexico (Burt This was especially mysterious and Peterson 1993), and the Siberian because an earlier study had shown Jay (P. infaustus; Blomgren 1971, that communal breeding does occur Ekman et al. 1994), the Eurasian in Green Jays in Colombia (Alvarez counterpart of our own Gray Jay. 1975). Why would the same species The Green Jays (Cyanocorax yncas) exhibit the behaviour in one place of Texas were another example of a but not in another? species where nonbreeders are pres­ The Gray Jay is also one of ent in family groups but apparently these exceptional species in which

VOLUME 20 UMBER 3 136 nonbreeders in the family group do below freezing. It brings its young not feed nestlings (Strickland and off the nest long before most migra­ Ouellet 1993) and for years I pon­ tory species have even returned to dered why. If multiple good reasons the boreal forest, let alone started to had been proposed for communal nest themselves. Under such condi­ breeding in other birds, why did tions, how could a pair of nesting Gray Jay nonbreeders fail to collect Gray Jays not benefit from the assis­ on these supposed benefits? In tance of an extra forager? And yet, Algonquin Park, about 20 percent the truth was, as I saw many times, of all breeding pairs are accompa­ that nesting Gray Jays actively nied by nonbreeders (most com­ harassed any nonbreeder that was monly one of their own young from present, including their own young the previous year) at the beginning from the year before. Parental hos­ of the breeding season around tility towards nonbreeders usually March 1. These nonbreeders are begins in the nest-building period usually males and have no chance, and reaches a peak in the nestling at that late date, to find an unoccu­ period. Most of the time any non­ pied territory and a mate, let alone breeder, if seen at all during the successfully breed. Why, then, since nesting season, is far from the nest. they have nothing better to do, do And, if the adults are present, they they not help Mom and Dad feed often chase it relentlessly. their current batch of nestlings? I readily confess that this Gray Would the nonbreeders not gain Jay behaviour in the nesting season valuable experience by doing so? completely stymied me. And, if any­ By increasing the production of thing, things got even more mysteri­ younger brothers and sisters, would ous before they got better. In 1994, they not improve the transmission Tom Waite, fresh from a Ph.D. of their common genes to the next based on his winter food storage generation? And how could they studies of the Gray Jay in Alaska, fail to improve the production of came to Algonquin Park and made nestlings by joining the adults in a surprising discovery. He found a feeding them? Remember, the act group of fledglings being fed, not of feeding nestlings by nonbreeders only by their parents, but also by was universally known by the GOSLWOPR (acronym for the loaded term, "helping". And surely, bands Green Over Standard Left, if any species needed help with its White Over Purple Right), their nesting, it was the Gray Jay. older brother born on the same ter­ Throughout the boreal and sub­ ritory the year before. And, over the alpine forests ofNorth America, this next two weeks, GOSLWOPR went species nests when the snow lies on to account for fully 22 percent of deep on the ground and the ther­ observed feedings. mometer usually indicates well The following year, we made ONTARIO BIRDS DECEMBER 2002 137 further observations of the same it does not occur in the nestling pair and confirmed that the behav­ period but can sometimes occur in iour we watched in 1994 was not a the fledgling period! Why would fluke. In particular, we saw that, in Gray Jay parents suppress allofeed­ our Algonquin Park Gray Jays at ing in the often wintry nestling peri­ least, allofeeding behaviour starts od and then allow it in the fledgling only in the fledgling period. The period, precisely when new food is 1995 nonbreeder tried to reach the starting to become readily available nest many times in the nestling and extra "help" from a nonbreeder period but he never got there. He would seem to be less important? was vigorously chased, or even This, then, was the challenge in struck in mid-air, whenever he trying to understand Gray Jay approached the nest. And yet, the social behaviour. In Part 2, to be day after the one young left the published in the next issue of nest, the nonbreeder began to feed Ontario Birds, I will present what it. Indeed, the 1995 nonbreeder Tom Waite and I propose as an accounted for 39 percent of all the answer to this challenge. In the feedings of the fledgling (compared meantime, why not try to solve the to 50 percent by the breeding male puzzle yourself? Come up with as and 11 % by the female). Since then, many hypotheses as you like, see if we have observed four more cases you can reconcile them with Gray of nonbreeders (at least one of them completely unrelated to the family involved) failing to feed nestlings but starting to feed them in the fledgling period. We have also observed at least one case where a nonbreeder refused to feed his younger fledged siblings, even though he was not prevented from doing so by the adults and in spite birdwatch of the fact that the fledglings often unique birding & nature products begged at him. 1907 Avenue Road When we had assimilated the Toronto, Canada M5M 3Z9 discovery that allofeeding some­ (1 km. south ofHwy. 401) times occurs in Gray Jays, but only Phone (416) 785-9222 after those siblings have fledged, we Fax (416) 785-3125 saw that we had an even bigger toll free 1-877-785-9222 problem to explain. No longer [email protected] could we ask "merely" why commu­ www.shopbirdwatch.com nal breeding does not occur in this David Renaud species. Now we had to explain why VOLUME 20 NUMBER 3 138

Jay behaviour as described above, might use to actually test your and try to imagine ways that you hypotheses. Have fun! *

*To be fair, you will need one more clue to come up with a hypothesis-or at least the same one we develop in our paper and through the same reasoning. Here it is: while we were watching adult Gray Jays feeding fledglings, we noticed that the young birds were fed by their parents much more frequently than in the nestling period.

Literature Cited Alvarez, H. 1975. The social system of the Gayou, D.C. 1986. The social system of the Green Jay in Colombia. Living Bird 14: Texas Green Jay. Auk 103: 540-547. 5-44. Skutch, A.F. 1935. Helpers at the nest. Auk Blomgren, A. 1971. Studies of less familiar 52: 257-273. birds, 162, Siberian jay. British Birds 64: Strickland, D. and H. Ouellet. 1993. Gray Jay 25-28. (Perisoreus canadensis). In The Birds of Brown, J.L. 1987. Helping and Communal North America, No. 40 (A. Poole, P. Breeding in Birds: Ecology and Evolution. Stettenheim, and F. Gill, editors). Academy Princeton University Press, Princeton, of Natural Sciences, Philadelphia, and New Jersey. American Ornithologists' Union, Wash­ Burt, D.B. and A.T. Peterson. 1993. Biology of ington, D.C. cooperative-breeding scrub-jays (Aphelo­ Strickland, D. and T.A. Waite. 2001. Does ini­ coma coerulescens) of Oaxaca, Mexico. Auk tial suppression of allofeeding in small 110: 207-214. jays help to conceal their nests? Canadian Ekman, J., B. Sklepkovych, and H. Journal of Zoology 79: 2128-2146. Tegelstrom. 1994. Offspring retention in Woolfenden, G.E. and J.W. Fitzpatrick. 1984. the Siberian Jay (Perisoreus infaustus): the The Florida Scrub Jay: Demography of a prolonged brood care hypothesis. Cooperative-breeding Bird. Princeton Behavioral Ecology 5: 245-253. University Press, Princeton, New Jersey. Emlen, S.T., H.K. Reeve, P.W. Sherman, P.H. Wrege, EL.W. Ratnieks, and J. Shellman­ Reeve. 1991. Adaptive versus nonadaptive explanations of behavior: the case of allo­ parental helping. American Naturalist 138: 259-270.

Dan Strickland, R.R. 1, Oxtongue Lake Road, Dwight, Ontario POA IHO

ONTARIO BIRDS DECEMBER 2002