Since retiring from UnB last year, the 66-year-old ornithologist has embraced her artistic side and returned to painting. A native of S\u00e3o Paulo, now 66, she lives with her husband in a spacious house with a garden in Park Way, near Bras\u00edlia\u2019s airport. Her two daughters, Natasha and Chantal, sometimes serve as models for her paintings.<\/p>\n
\nBird behavior
\nInstitution<\/strong>
\nUniversity of Bras\u00edlia (UnB)
\nEducational background<\/strong>
\nBA in Liberal Arts from Pine Manor College (1979), BA in Biology from UnB (1983), MA in Education from Lesley University (1984), and both an MS (1986) and PhD (1991) in Zoology from the University of Oklahoma
\n<\/div>\n
You\u2019ve studied a wide range of bird species. Which was the most remarkable?<\/strong> Aren\u2019t competition and cooperation opposing forces?<\/strong> At some point, they must stop the killing, right?<\/strong> Otherwise, the species wouldn\u2019t survive.<\/strong> Openings for researchers in animal behavior used to be limited in Brazilian universities<\/p><\/blockquote>\n In what ways do guira cuckoos cooperate?<\/strong> How does cooperative breeding work?<\/strong> Why is it important to balance field observations with experimental research?<\/strong> You have also run captive studies, haven\u2019t you?<\/strong> Your team also found that grassquit vocalizations vary by region.<\/strong> Luc Viatour\u2009\/\u2009Wikimedia Commons | Dario Sanches\u2009\/\u2009Wikimedia Commons<\/span>The blue-and-yellow macaw\u2014now frequently seen in Bras\u00edlia; the blue-black grassquit\u2014whose song changes depending on the region (top right<\/em>); and the guira cuckoo\u2014a known nest raiderLuc Viatour\u2009\/\u2009Wikimedia Commons | Dario Sanches\u2009\/\u2009Wikimedia Commons<\/span><\/p><\/div>\n Was vocal communication a core focus of your research, or more of a side project?<\/strong> Your master\u2019s was on a rodent species.<\/strong> Why?<\/strong> What has changed since you began researching animal behavior at UnB?<\/strong> That colleague\u2019s comment is pretty shocking…<\/strong> You\u2019ve studied dragonflies, primates\u2014even whales.<\/strong> What do such wildly different animals have in common?<\/strong> In tropical forests, reproduction can occur throughout the year and that reduces the intensity of mate competition<\/p><\/blockquote>\n In 2014, you and Glauco Machado of the University of S\u00e3o Paulo coauthored Sexual Selection: Perspectives and Models from the Neotropics <\/em><\/strong>[Oxford, UK], arguing that sexual selection in tropical regions operates differently than it does in temperate zones.<\/strong> What sets it apart?<\/strong> What other ideas have you helped challenge or change?<\/strong> Are you interested in how urbanization affects bird behavior?<\/strong> In S\u00e3o Paulo, for example, you\u2019ll hear thrushes singing at 2 a.m.<\/strong> Some bird species living near airports shift their singing schedule to avoid the loudest times with frequent takeoffs. Others actually change the pitch of their songs<\/p><\/blockquote>\n How is life one year after retiring from UnB?<\/strong> What\u2019s it like to take up an old passion?<\/strong> How long have you been painting portraits?<\/strong> How did biology enter your life when you were clearly already set on art?<\/strong> The above interview was published with the title “Regina Macedo: The art of observation<\/strong>” in issue 352 of April\/2025.<\/p>\n","protected":false},"excerpt":{"rendered":"S\u00e3o Paulo native from UnB who helped revise concepts about sexual selection in the tropics and cooperative breeding has dedicated herself to another passion since last year: painting","protected":false},"author":3,"featured_media":568119,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[161,159],"tags":[209,224,200,218,266],"coauthors":[1601,5968],"class_list":["post-568110","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-interview","category-science","tag-biology","tag-ecology","tag-environment","tag-ethology","tag-zoology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/568110","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=568110"}],"version-history":[{"count":1,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/568110\/revisions"}],"predecessor-version":[{"id":568147,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/568110\/revisions\/568147"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media\/568119"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=568110"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=568110"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=568110"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=568110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nI\u2019ve mentored students working with all sorts of species, but the ones I found most rewarding were those where I was out in the field myself. My PhD focused on the guira cuckoo, and I continued that research for over a decade. It explored the intersection of competition and cooperation\u2014one of the big questions in animal behavior: how competition operates within cooperative social systems. The grassquit started out as a small project\u2014something more manageable for a master’s student who was afraid of climbing trees. This bird performs an incredible, acrobatic display and raises all sorts of questions related to sexual selection, which was a topic I hadn\u2019t delved into yet but found fascinating. So I ended up going into sexual selection research, starting with the grassquit. These are two very different fields of research\u2014cooperation and sexual selection. The guira cuckoo and the grassquit became the mainstays of my research.<\/p>\n
\nThey are, but in any social system, they have to coexist in balance. You\u2019re never going to eliminate competition entirely, nor achieve flawless cooperation. That messy interface was precisely what fascinated me. Guira cuckoos live in social groups of up to 13 adults. They form pairs\u2014though not necessarily monogamous ones\u2014and within the group, several females reproduce. Both males and females compete for nest space. Often, females that haven\u2019t started laying will throw out the eggs of those who have. And it doesn\u2019t stop there\u2014sometimes they\u2019ll even kill the hatchlings. Competition for nesting space can be brutal.<\/p>\n
\nExactly. Eventually, they have to stop destroying eggs so that the nest can develop\u2014and some chicks can survive. One hypothesis I explored was that the individuals doing the sabotaging were those who had failed to reproduce during that nesting round. Typically, the dominant female in the group hierarchy is the last to begin laying. Until then, she clears the nest\u2014removing any eggs that show up\u2014to reserve space for her own clutch. Males likely toss eggs or kill chicks when they haven\u2019t mated, though it\u2019s hard for them to know which offspring are theirs. Ultimately, the group has to reach a tipping point where everyone commits to the nest and moves forward together. Competition peaks at the start of the breeding season, which in Central Brazil begins with the rainy season, around August or September. At that stage, the dominance structure is often still in flux. But if the group doesn\u2019t succeed in raising chicks by the season\u2019s end, they\u2019ve lost their window\u2014once the dry season sets in, it\u2019s game over. The climate itself places a boundary on competition. And then there\u2019s the group\u2019s genetic structure\u2014related individuals change the hierarchical dynamics. There\u2019s still a lot we don\u2019t fully understand. I hope more researchers build further on this line of research.<\/p>\n
\nIt\u2019s tied to the relationship between sociality and predation risk. When I used to climb trees to monitor nests, I\u2019d often see one bird standing guard nearby while the others foraged farther away. That sentinel would give alarm calls at the first sign of danger, triggering the whole group to rush back and erupt in frantic vocalizations. Guira cuckoos forage on the ground, moving together like a miniature herd. One of the clearest advantages of group living is protection from predators. Another important mechanism is cooperative breeding.<\/p>\n
\nTake the campo flicker, for example: only one breeding pair is active, while the \u201chelpers\u201d\u2014often their grown offspring from previous seasons\u2014stand guard at the nest when their parents are away. That system is actually more common than what we see in guira cuckoos, whose nesting strategy has been documented in just 12 to 15 species out of more than 9,000 known bird species. Cooperative breeding seems to be more frequent in tropical regions\u2014likely because the environment is more stable, without the harsh winters. One of my students, Raphael Igor, did extensive research on the campo flicker.<\/p>\n
\nScientific inquiry often begins with a random observation in the field. Just today, on my way home near the airport, I noticed a field teeming with hundreds of southern lapwings. That kind of setting is a perfect starting point to ask questions like: Why is this species so cooperative? What draws them to this spot? You\u2019ll see 200, sometimes 300 of them congregating daily. Field observation is essential at first, to describe a phenomenon, pose a question, or develop a hypothesis.<\/p>\n
\nYes, I maintained an aviary at UnB for 20 years, where we housed grassquits. It\u2019s often a faster route to answering questions\u2014we did some great experiments there. We noticed that grassquits behaved a bit differently in captivity. For instance, in the aviary, they would sometimes perform their signature jump without singing\u2014but in the wild, I never saw a single jump that wasn\u2019t accompanied by their distinct vocalization. In nature, they often perch and sing without leaping. But in captivity, silent jumps were quite common\u2014possibly because they didn\u2019t need to attract mates or stay alert for predators, or maybe just to conserve energy.<\/p>\n
\nYes, that was a project by one of my final students, Edvaldo Silva Jr. It began when I was browsing bird recordings in the Cornell Lab\u2019s archives and heard a Caribbean grassquit. Its vocalization was noticeably different from the ones we\u2019d recorded in Brazil. Birds typically have common dialects, but when a species is widely distributed, their vocalizations become slightly different in each place. So let\u2019s say you introduced a Central Brazilian grassquit into the Caribbean. Two things might happen: the females there might find his song appealing\u2014or they might not recognize it at all. These regional song differences matter a lot when it comes to reintroducing endangered birds. They can make or break a successful reintroduction\u2014and over time, may even drive speciation itself, leading to the emergence of entirely new species.<\/p>\n![\"\"](\"https:\/\/revistapesquisa.fapesp.br\/wp-content\/uploads\/2025\/11\/RPF_entrevista-regina-macedo-Passaros-2025-06-1140.jpg\")
\nBioacoustics became a research line I introduced in our lab at the University of Bras\u00edlia, back when it was still fairly uncommon in Brazil. It all started with a student, Pedro Diniz, who wanted to study the rufous hornero. I didn\u2019t have any recording equipment, but he had a recorder\u2014and tons of passion. He made real progress, completed a solid PhD, and that\u2019s when I started getting involved. I took a course in bioacoustics, brought in collaborators, and learned how to make recordings myself. Other labs were already researching bird vocalizations at the time, but not necessarily in the context of behavior.<\/p>\n
\nAfter I graduated with my biology degree from UnB, I got a job as a secretary at the Canadian Embassy. Almost a year in, I went back to UnB to pick up some documents and happened to bump into one of my former professors, Cleber Alho. He asked, \u201cWant to go to the US for a master\u2019s on a scholarship?\u201d I said, \u201cAbsolutely! But what would I be doing?\u201d I was sent to the University of Oklahoma with a project they wanted me to work on\u2014on rodent taxonomy. I spent the whole program visiting museum collections, taking 24 measurements on each tiny skull of Bolomys lasiurus<\/em> using a caliper. By the end of my master\u2019s, I was completely disillusioned. I thought, \u201cThis isn\u2019t biology\u2014not the kind I love.\u201d I didn\u2019t know what I did love, until I took an ornithology class taught by Douglas Mock. He focused a lot on animal behavior in his lectures. I became hooked. \u201cThis is what I\u2019ve been looking for,\u201d I thought. My advisors\u2014Michael Mares at the University of Oklahoma and Cleber Alho at UnB\u2014fully expected me to stay in taxonomy. But the moment Michael left for a conference, I bolted from the museum. When he got back, I apologized profusely and told him I was switching to behavior. I\u2019d already moved to a new lab and arranged for a new advisor, Gary Schnell.<\/p>\n
\nDuring my first ten years, I felt like I was working in the dark. At the time, there were very few academic openings for researchers in animal behavior anywhere in Brazil. I remember once, a student enrolled in a master\u2019s program under a genetics professor but also wanted to study behavior. We co-led a project using flies. When we presented it to the grad committee, a faculty member from another department laughed and said, \u201cSince when do flies exhibit behavior?\u201d I thought, \u201cDear God, I\u2019m stuck in the Middle Ages.\u201d It took years before more labs emerged across Brazil and animal behavior gained recognition as a serious field.<\/p>\n
\nI returned to Brazil with a strong foundation in sociobiology, which was already well established\u2014especially in the US [sociobiology explores social behavior in animals, including humans, through the lens of evolution, psychology, and genetics; see the E. O. Wilson obituary<\/em> in Pesquisa FAPESP issue n\u00b0 312<\/a><\/em> and the Carlos Brand\u00e3o interview in issue n\u00b0 317<\/a><\/em>]. When I taught my course on animal behavior and sexual selection, I always began with a disclaimer: explaining a behavior, even in humans, is not the same as approving of it. People sometimes lean on biology to justify uncomfortable behaviors like infanticide\u2014which, yes, occurs in many species, including humans. Yes, we can explain it biologically, but that doesn\u2019t mean it\u2019s acceptable to us. You can\u2019t just take evolutionary or ecological reasoning and apply it directly to human behavior\u2014it doesn\u2019t work that way, and it can send the wrong message. That distinction was often hard for people to grasp. In 2011, I launched a class called Sexual Selection and Reproduction, and 130 students enrolled\u2014but there were only 25 seats. It took a while for people to realize I wasn\u2019t going to teach the Kama sutra<\/em>\u2014that it was about animal biology.<\/p>\n
\nThe underlying principles are the same. You can apply the same behavioral hypotheses to humans, mammals, reptiles, even insects. What differs is each species\u2019 biology\u2014and the specific ways selective pressures act on them. Ultimately, all organisms are driven by three biological imperatives: survive, find food, and reproduce. Sociality is another common theme. Living in groups helps reduce predation risk\u2014but it also brings new challenges, like competition for food and mates. That dynamic plays out across the entire animal kingdom, from backyard lizards to humpback whales. I didn\u2019t usually seek out new species to study\u2014but my students often pushed me there. One of them, the brilliant Diana Lunardi, wanted to study humpback whales. I said, \u201cDo you see any humpback whales around here in the Cerrado (wooded savanna)?\u201d But she teased my interest in other questions\u2014like foraging, predation, and mating\u2014and eventually convinced me.<\/p>\n
\nIn the tropics, there\u2019s little to no seasonality. In temperate zones\u2014where winters are harsh\u2014breeding seasons are very short, and that shapes behavior. It tends to increase competition for mates, for instance. In places like the Amazon, reproduction can occur throughout the year and that reduces the intensity of mate competition. The problem Glauco and I kept running into\u2014and which eventually led us to write the book\u2014was the assumption among many North American and European researchers that their findings applied globally. These researchers would study just a handful of species\u2014often in laboratory settings\u2014and then make sweeping claims about animal behavior. Glauco and I disagreed. We pushed back and gathered a broader community of scientists to challenge those assumptions. We were able to demonstrate that the patterns we saw in Brazil and across the tropics simply didn\u2019t align with the behavioral findings coming from US and European researchers. The tough part was getting published. Our findings didn\u2019t fit the frameworks that journal reviewers\u2014most of them from the Global North\u2014expected. I would argue that it was because we weren\u2019t working with zebra finches, the standard model organism for so many behavioral studies. Nor were we using lab-bred budgies, which are mass-reared in the US and Europe. We were studying wild tropical species, in their natural habitats. The book was a protest\u2014a challenge to dominant ideas that didn\u2019t suit the tropics. And little by little, as more Brazilian researchers enter international circles, our conceptual framework has gained acceptance [see<\/em> Pesquisa FAPESP issue n\u00b0 244<\/em><\/a>].<\/p>\n
\nI contributed to early discussions on using genetics to investigate kinship, which turned out to be essential for understanding animal behavior\u2014especially in birds. Around four decades ago, the prevailing view was that birds were monogamous, mammals were not, and fish were… well, hit or miss. Sure, birds often paired off\u2014one male, one female\u2014but what went on inside the nest was a whole different story. Often, the chicks didn\u2019t belong to the male partner. We even found cases where the chicks weren\u2019t related to the nesting female. From an evolutionary point of view, that kind of genetic mixing is beneficial\u2014it boosts genetic diversity. We found that in many species, rates of extra-pair mating\u2014either copulation or paternity\u2014were surprisingly high. I believe this behavior is closely tied to predation\u2014arguably one of the most brutal forces in natural selection. In the case of the grassquit, 80% of the broods in one of our study areas were eaten by predators. But grassquits breed multiple times\u2014four or five\u2014during the rainy season. A male will mate not only with his nest\u2019s female, but also with females from surrounding nests. He spreads his genes far and wide, increasing the odds that some of his offspring will survive. The evolutionary advantage here is avoiding total reproductive failure\u2014ensuring that at least one chick makes it. And for the species as a whole, it enhances genetic diversity, which is also beneficial.<\/p>\n
\nSome of my students have explored this topic. One in particular\u2014Renata Alquezar\u2014did a fantastic and important PhD project showing how airport environments influence bird vocalizations. Noise pollution has major effects\u2014not just on song, but on birds\u2019 biology and how they interact with one another. Some species shift their singing schedule to avoid the loudest times with frequent takeoffs. Others actually change the pitch of their songs. They start singing at a higher frequency and boost their volume\u2014much like we shout over the noise in a crowded bar.<\/p>\n
\nAt 2 a.m.? That\u2019s far from normal. We\u2019ve also found that some birds just can\u2019t adapt to highly urban areas\u2014they disappear. The ones that stick around are the most flexible, the best urban adapters. Species like the rufous hornero, house wren, thrush, and great kiskadee are urban regulars\u2014they thrive in city environments. But many others just can\u2019t cope. Back in the 70s and 80s, campo flickers and guira cuckoo flocks were everywhere in Bras\u00edlia. Now, they\u2019re a rare sight. On the flip side, we\u2019re now seeing a surge of blue-and-yellow macaws\u2014birds typically found in the Amazon\u2014showing up in large numbers. Something is driving them into this region.<\/p>\n
\nStepping away from the university wasn\u2019t easy. I still had work to do and students to mentor. But I\u2019ve always believed in leaving the party while it\u2019s still lively. And I had this long-standing passion for art that I was finally ready to explore. I set out to start a new path\u2014and it\u2019s been wonderful. No pressure, no stress. I\u2019m still getting used to life without deadlines. It\u2019s strange, after decades of rushing from task to task.<\/p>\n
\nMy love of painting never faded. I\u2019ve always lived with one foot in the art world. Even at my university, I\u2019d find myself noticing the way light hit someone\u2019s ear and thinking, \u201cwhat a beautiful color.\u201d I kept a modest artistic practice over the years. I painted when I had time and occasionally put on a show. So this new phase isn\u2019t exactly a rediscovery. I started taking classes again\u2014with instructors who were young, 30-something painters… I had to step back into the role of student, hearing feedback and being corrected. That part took some getting used to. I still read a lot about genetics, physiology\u2014biology in general. I\u2019ll read one science book, then two fiction books to balance it out. I love short stories with happy endings\u2014they help restore my faith in humanity. I especially enjoy painting portraits. Landscapes are fun too, but they\u2019re easier\u2014you can add a branch or move a rock and no one questions it. But capturing the human face? That\u2019s a whole different level. You need real precision to get the expression, the eyes, just right.<\/p>\n
\nSince I was about seven or eight. I used to sit my little sisters down and demand they stay still so I could draw them. But of course, they\u2019d squirm and protest\u2014it never quite worked out. These days, my daughters are my favorite models. For Christmas, I always ask, \u201cCan I have an hour in the studio to photograph you?\u201d Then I paint from those photos. It\u2019s my way of keeping them close. One lives in S\u00e3o Paulo, the other in Bras\u00edlia. I even managed to hold a few art shows while I was still at UnB. My most recent one was last year at Brazil\u2019s Supreme Court of Justice.<\/p>\n
\nMy dad was in the Air Force and got transferred to Canada when I was about six. We came back when I was nine, and at that point, I couldn\u2019t read or write in Portuguese and barely spoke it. My mom took a job at the American School so my sisters and I could study there. By the time I was 16 or 17, I had fallen in love with biology. After high school, I got a scholarship to study fine arts in the US. I moved to Boston alone at 18. I spent two years studying fine arts, but I also took electives in marine biology, genetics, and cell biology. I loved every one of them. But art was still my main focus. Then I came back to Bras\u00edlia and had a moment of clarity: \u201cI\u2019m not going to make a living off painting.\u201d Honestly, even today, I don\u2019t think I could. I made the practical choice and enrolled in biology at UnB. I\u2019ve never once regretted it.<\/p>\n