Curtis Adkisson (see photo, this page). Blue jays (Cyanocitta cristata) are abundant in human-dominated habitats throughout eastern North America and are spreading westward. It is unclear how hundreds of blue jays exist in the citrus groves (Keck Grove) adjacent to Archbold Biological Station (S of Archbold Rd.). One clue comes from their caching of acorns obtained from the Red Hill section of Archbold, to the north, and from the mixed woods and scrub to the west. By placing transmitters on selected birds, Adkisson established that these birds spend virtually all their time in the groves, except when they are harvesting acorns to cache in their home ranges. In 1997 and 1999 certain individuals regularly flew several round trips of at least 4 km daily for 2 months, in caching about 5000 acorns from Red Hill, and from areas west of the grove, in the grove. During winter (October-March), they appeared to remain in the immediate vicinity of those caches, virtually undetectable unless wearing an active transmitter. A hypothesis is that this is a response to wintering Cooper’s hawks. In the dry fall of 2000, caching activity was lower than in the previous 8 years, perhaps in response to a poor acorn crop. The effect of this disturbance on jay populations is unknown. By continuing to band and transmitter jays living in the Keck Grove, Adkisson hopes to learn how this fluctuation in local climate has affected their abundance.

Robert Curry’s (see photo, this page) research on Florida scrub-jays (Aphelocoma coerulescens) during 1999-00 focused on the influence of ecological factors on timing of breeding. Curry’s work included 4 months at Archbold during a sabbatical when he edited and analyzed the Station’s weather data sets, and integrated these with data on scrub-jay demography (1970-00) and on availability of foods used by the jays (1988-00) (see also; Bird Research, pages 10-11). This research focuses in part on the possible effects of climate change on breeding phenology, which could have implications for demography and population persistence. For example, egg-laying date in the Mexican jay (A. ultramarina) has advanced in Arizona in association with warmer spring nights. Evidence from Archbold scrub-jays provides a counter-example: there has been no trend in laying date over the past 3 decades. Over the same period, climate variables have changed little in peninsular Florida. Whether scrub-jay phenology would shift even if Florida’s climate were to change is questionable, because the timing of breeding appears to be determined by abundance of food (acorns, lizards, and frogs) well in advance of laying and not by weather just prior to clutch initiation. Relationships between phenology, demography, and food resources suggest that landscape-level habitat patterns are important for scrub-jay population success. Destruction of seasonal wetlands, though used little by foraging scrub-jays, could reduce herp abundance, delay onset of scrub-jay breeding, and influence demography. Habitat fragmentation, and resulting reduction in fire frequency and changes in successional dynamics, could affect acorn production, resulting in further consequences for scrub-jay demography.

Hugh Ellis (see photo, this page). Previously, Glen Woolfenden, Reed Bowman, and Ellis had determined that the daily energy budgets (DEB’s) of male suburban Florida scrub-jays (see also; Avian Ecology, pages 12-13) were twice as high as the DEB’s of males in natural habitats at Archbold Biological Station. In summer 1999, we were interested to learn if that difference was reflected in the basal metabolic rate (BMR). BMR is a function of evolutionary selection, whereas DEB is an index of ecological demands. By looking at BMR, we could determine if there was a physiological explanation for the difference in DEB’s and if there were metabolic differences related to either season or gender. No difference in BMR was detected between day and night or among seasons (spring, summer, fall). We were unable to show a molting effect on BMR. We found that suburban breeding males have a BMR 14% higher than breeding males in natural habitat, but it is not significantly higher. Scrub-jay BMR is 81.2% of that expected for a passerine bird of its size, including the blue jay. This is consistent with our findings that scrub-jay DEB is low.

Ronald Mumme (see photo, this page), a regular visitor to Archbold since 1986, continued his research on the conservation biology of Florida scrub-jays. He, and Stephan Schoech, have primary responsibility for censusing and maintaining records of the scrub-jay population in the scrub-jay "south tract," (tracts 19,30,31, & Hicoria; see map [b], this page) the portion of Archbold south of the main scrub-jay study area (the scrub-jay "demography tract"). During 1999-00, Mumme focused on the extent of roadside mortality in the jays along Old State Road 8 since the 1995 widening of the right-of-way. Results obtained from the experimental tract during 1986-95, before the right-of-way widening, were published (2000) in Conservation Biology in a paper co-authored with Schoech, Glen Woolfenden, and John Fitzpatrick. [Mumme, R.L., S.J. Schoech, G.E. Woolfenden, and J.W. Fitzpatrick. 2000. Life in the fast lane: demographic consequences of road mortality in the Florida scrub-jay. Conserv. Biol. 14:501-512.]

Stephan Schoech (see photo, this page) has been collaborating with Reed Bowman on a study of the nutritional physiology of Florida scrub-jays. They noticed that suburban jays, which Bowman has been studying since 1992 (see also; Avian Ecology, pages 12-13), always initiate reproduction earlier than jays in natural habitats at Archbold. This difference may be attributable to abundant anthropogenic foods available in the suburbs and may be expressed as a difference in the reproductive physiology of breeding females between the two sites. A 1998 pilot study compared a number of physiological parameters in breeding females at the two populations, e. g., plasma levels of calcium, protein, and the reproductive hormones luteinizing hormone (LH) and estradiol (E₂), as well as total body lipids, a measure of condition. Results suggested that Archbold jays might be limited by dietary proteins. Furthermore, the utilization of stored fats by females at both sites in the period immediately preceding egg-laying hints at a role for lipids in a female’s decision of when to initiate reproduction.

An NSF grant has allowed them to conduct follow-up experiments to determine whether protein, fat, or a combination of both were critical. During 2000, in the scrub-jay "south tract" (see Mumme, above & map [b], this page) of Archbold, they provided jay families with custom-made supplemental diets that were either high in fat or high in fat and protein (a diet high in just protein was unpalatable). All supplemented jays advanced the date of clutch initiation relative to unsupplemented controls. Although females fed fat plus protein tended to lay earlier than those fed fat alone, there was no statistical difference. Supplemented females laid larger clutches and had more young survive to independence, suggesting a fitness benefit to early breeding. These findings fail to support the hypothesis that jays in natural habitats are protein limited but rather suggest that the high-energy fat is important by increasing the overall condition of a female. Future work includes endocrine analyses (LH, E₂, and leptin) of the blood samples from 2000. Information about the hormonal status of breeding females will give us a better understanding of the effect of nutrition on the reproductive physiology of female scrub-jays.