Review sharpens focus on corticosterone testing in psittacines
Bottom line
A new review in Animals highlights how understanding corticosterone in psittacine birds is becoming more clinically relevant, especially as veterinarians and researchers look for better ways to interpret stress in parrots and related species. The paper, published July 11, 2026, by Timothy J. Brunner, Hailey B. Penticoff, and Thomas N. Tully Jr., argues that corticosterone data can be useful only when clinicians pay close attention to how samples are collected, what time window they represent, and which outside factors may be influencing results. The authors frame corticosterone as a key hormone in avian stress physiology, tied to the hypothalamic-pituitary-adrenal axis and linked with homeostasis, glucose mobilization, immune function, behavior, feather condition, reproduction, and responses to veterinary handling. (mdpi.com)
Why it matters: For veterinary professionals, the message is less about a new diagnostic breakthrough and more about better clinical interpretation. Recent psittacine work has shown that routine handling and restraint can significantly raise corticosterone in parrots, which means the exam room itself may alter the biomarker being measured. At the same time, feather and fecal measures may offer a less invasive window into longer-term stress, though those methods come with their own technical limitations and don’t capture the same time frame as blood sampling. For avian clinicians, that makes sample choice, timing, and context central to welfare assessment, behavior workups, and research design. (pubmed.ncbi.nlm.nih.gov)
What to watch: Expect more work on standardized sampling methods and on how corticosterone measures might be integrated with behavior and clinical findings in companion psittacines. (mdpi.com)
Key facts
- Article type
- Review
- Journal
- Animals
- Publication date
- July 11, 2026
- Topic
- Corticosterone in psittacines
- Main takeaway
- Corticosterone data are useful only with careful attention to sample collection, timing, and outside factors
- Physiologic role
- Principal avian glucocorticoid in hypothalamic-pituitary-adrenal axis signaling
- Clinical relevance
- Linked with energy mobilization, behavior, immune responses, and other physiologic functions
- Sampling caveat
- Blood reflects acute responses, but capture and restraint can affect results
- Alternative matrices
- Feather and fecal measures may offer less invasive, longer-term stress assessment
A newly published review in Animals takes stock of what veterinarians and avian researchers now know, and still need to clarify, about corticosterone in psittacines. Published July 11, 2026, “Continued Advancement in Understanding of Corticosterone in Psittacines” emphasizes that stress-hormone data in parrots can be clinically meaningful, but only if veterinarians understand the biology behind the number and the limitations of the sampling method used. (mdpi.com)
That’s an important point because corticosterone has long been treated as a shorthand marker for avian stress, yet interpretation is rarely straightforward. In birds, corticosterone is the principal glucocorticoid involved in hypothalamic-pituitary-adrenal axis signaling, and it influences energy mobilization, behavior, immune responses, and other physiologic functions. The new review places that biology in a specifically psittacine context, where welfare concerns, behavioral disorders, captivity-related stressors, and the realities of clinical handling can all complicate what a measured value actually means. (mdpi.com)
The authors say clinicians and readers need to distinguish among the different matrices used to measure corticosterone, because each reflects a different slice of time and a different kind of stress exposure. Blood sampling can capture acute responses, but it is also highly vulnerable to the stress of capture and restraint itself. Feather corticosterone may reflect hormone exposure during feather growth and can support longer-term welfare assessment, but experts have cautioned that feather measures are shaped by molt timing, sample mass, and other unresolved technical issues. Fecal metabolite testing offers another less invasive option, especially for behavioral and welfare questions, but it likewise requires careful interpretation. (mdpi.com)
That concern about handling is not theoretical. A 2023 PubMed-indexed study in Hispaniolan Amazon parrots found that handling and restraint induced a significant rise in plasma corticosterone over the course of an hour, underscoring how quickly a clinical encounter can alter the very biomarker under study. The authors of that paper argued that understanding this response could help clinicians better judge how routine handling affects patient condition and diagnostic test results. (pubmed.ncbi.nlm.nih.gov)
The broader literature also suggests corticosterone may be relevant beyond stress scoring alone. In captive African grey parrots, researchers have reported an association between feather-damaging behavior and corticosterone metabolite excretion, supporting the idea that endocrine data may add context in some behavioral cases, even if it should not be used in isolation. More recent budgerigar research has also shown that repeated human-associated stressors can influence corticosterone responses, reinforcing the need to think carefully about how husbandry, restraint, and repeated sampling shape endocrine findings. (pmc.ncbi.nlm.nih.gov)
Expert reaction in the form of direct commentary was limited, but the surrounding professional context is clear. The Association of Avian Veterinarians continues to emphasize avian health and welfare advancement through science and education, and the review’s practical message aligns with that mission: stress biomarkers are useful only when paired with sound clinical judgment, species knowledge, and attention to welfare. That is especially relevant in companion bird medicine, where pet parents may present concerns about feather quality, behavior change, chronic stress, or husbandry, and clinicians are often asked to translate emerging welfare science into practical care plans. (aav.org)
Why it matters: For veterinary teams, this review is a reminder not to overread a corticosterone result. A blood value collected after transport, restraint, or prolonged handling may reflect the visit as much as the bird’s baseline state. A feather result may be more useful for retrospective welfare questions, but not for acute clinical decision-making. In practice, that means corticosterone is best viewed as one data point alongside history, physical exam findings, behavior, feather condition, social environment, and husbandry review. Used that way, it may strengthen welfare assessments and research protocols in psittacines, rather than muddy them. (mdpi.com)
What to watch: The next step is likely more standardization, including clearer guidance on sample type selection, collection timing, and interpretation thresholds for different psittacine settings. As more studies connect corticosterone patterns with clinical signs, behavior, and welfare outcomes, the field may move closer to using these measures more confidently in both research and specialty avian practice. (mdpi.com)