I have dedicated several posts to the effects of a change in weather that I have observed in the roe deer males (e.g., Roe deer observation (May 30, 2024) – patrolling after a change in weather and some thoughts on roe deer hormonal rates) but also in females (Roe deer observations (first week of June, 2024) – change of fawn-raising site during cold weather).
The last week (and a half) has been characterized by a dramatic drop in temperatures (from ca. + 12 – 15°C down to ca. 10°C), and the roe deer males exhibited a response when the shift began.
Over the past 2 days, I believe I noticed a transition in fawn-raising site in one of the roe deer families (see the link above) whereby the female brought the fawn from an edge-type riparian grove into a mature forest habitat where the microclimate is warmer and more stable.
This family is fortunate because the two habitats are separated by as little as few metres (they used to comprise a united riparian forest block before some of the forest was cleared to make space for a hayfield).
I believe they could make the adjustments based already on minor fluctuations in weather.
Also, in this family, the male is able to keep in close touch with the female and the fawn because there are foraging as well as resting sites nearby that the male can use without infringing on the mother and fawn’s resources (e.g., orchards, another hayfield which is more exposed and where the fawn does not venture).
Thus, the shifting between the habitat patches was not characterized by any dramatic changes.
I believe that other roe deer families do not have such opportunities to transition easily between habitat types and they must make firm choices (i.e., if they leave one patch, this has to be for a longer time due to the arduous journey for the fawn and they cannot just go to and fro on a nightly basis).
Also, in these families, the riparian habitat is very limited and the males (even the mothers) must frequently forage quite far from the fawning site (the males are using highly suboptimal foraging habitats, e.g., ditch-sides, road-sides and I have seen a yearling female who was probably not a mother resting on rapeseed field which is certainly not preferred by the roe deer but the mother and fawn needs must be prioritized etc.).
Last night, the temperature suddenly dropped to +5°C, and due to the high level of humidity, it felt almost freezing (0°C).
I believe that this dramatic change forced some of the roe deer females to have their fawns travel with them to warmer habitats/patches.
While I did not observe the movement, nor I could locate the consequent site, the early hours of June 11 saw some notable roe deer male activity.
At first, I though the males were patrolling the way they did before – upon a drop in temperature.
I believe that when the temperatures become lower, the roe deer males experience a hormonal change that incites leadership and provokes them not to defend their territory but to plan ahead.
I believe that during cold weather (e.g., during winter) males take charge and they attempt to choose suitable foraging/resting/travelling sites for their families and (during winter) social groups.
This might coincide with some respective change in the female hormonal response to cold weather which I will currently avoid to touch upon because it is not the point of this post.
I have come to regard the male ‘territorial’ behaviour as that of actually selecting resources for their family units and announcing these requirements and decisions to neighbours.
Rather than aggressively excluding other males, I have come to see this behaviour as peaceful negotiation among neighbours so that each female and her young of the year came by the best resources that are claimed and advertised on behalf of them by the male.
Later on, when the female has given birth already, I believe that a drop in temperature, once more, elicits patrolling type of behaviour whereby the male is planning ahead what resources will be needed further on during the fawn’s development and, once again, neighbours confer and listen in to adjust their own projects so that they were compatible on a population level.
I believe patrolling is all about communication among local families that, even during spring and summer, still operate as a social unit.
During these conversations, necessities are communicated based upon weather, loss or gain in habitat, resource distribution, number of fawns born etc.
Aggression is involved but I think that the aggressive aspect to these conferences is not derived from intermale aggression.
We tend to view emotional, hormonal etc. responses as directed toward other individuals.
But hormonal responses are observed in life forms that hardly recognize one another as anything other but an environmental stimuli akin to abiotic factors of influence.
It is very difficult to accept, for example, that aggression could be a response to abiotic environment and that it could be worked out together with other males rather than aimed at other males.
E.g., if aggression is a natural and beneficial response that ensures community welfare, it should not be suppressed but rather it should be played out to that community’s profit.
We have come to insist that animals compete with each other and that is the cause to aggression which we sometimes observe but my theory is that aggression is, truly, a response to an overall anticipation of some consequences (as well as an attempt to moderate these consequences) and that aggressive acts between individuals might be observed not because these individuals are aggressive toward one another but because both individuals agree that the aggression which has been evoked in one of them or both of them, is necessary to ensure some benefit that is perhaps difficult to perceive for humans who are no longer hormonally affected by, e.g., weather and whose bodies cannot subtly predict what is to come.
It is, for example, easy to accept that abiotic factors can provoke fear responses (and the respective hormonal states).
It seems unwise for us to be angry about bad weather because there is nothing we can do about it anyway.
Meanwhile, it is possible that other species have figured out methods of affecting their chances via playing out their hormonal messages that no longer only serve to prime their own body to survive the adverse conditions but that might be engaged in a manner that protects ‘many bodies’, i.e., their families, their social group.
I will not delve deeper into this, presently, but I will give a simple example from the plant kingdom where injured individuals or individuals subjected to some types of stresses (e.g., drought) emit volatile compounds or protein-based signals (e.g., on root level) that reach other individuals who become informed on the expected peril and prime themselves accordingly (get ready to defend themselves or to endure adversity).
It is thought that plants perhaps evolved such distant communication to notify their other body parts and not their neighbours at all (e.g., signals emitted by pest-injured leaves to quickly notify other leaves which are not yet injured).
However, as most plants are linked, for example, via mycorrhizal networks which also ensure mutualism among plants themselves, it is possible that not only social animals avoid competition because collaboration is a greater guarantee to survival, but so do plants (e.g., individuals would compete to some degree for localized resources, light etc. but there is a threshold above which the loss of an individual or perhaps the loss of a part of a local population of individuals might lead to very undesirable consequences such as overtaking of this niche by other species that are far more dominant).
If one roe deer male responds to his prognostications of what is to come and how things should be aggressively, it might make sense for other males to indulge this aggression because it could ‘prime them’, as well.
For example, they might gain insight into what is to be expected but also they might take on this aggression and follow up on how it impacts them before they must face the adverse conditions as such.
Namely, they might see if the aggression by one male from their local population causes them to succumb to overwhelming distress because if it does, it might suggest that they have to adjust their behaviour so that they could survive the conditions that the aggression predicts.
Thusly, aggression itself could serve as a community signal (similar to a newspaper article which comments on some expected changes) and as all males are involved, the population, as a whole, might come by an impression of the overall status of their range on a regional and not just family level (because any one family is affected by what is happening on the ranges of other families).
Similarly, if a male is very aggressive regarding some resources he wishes to keep for his family, other families might oblige by keeping out (not engaging with his aggression) so that they were not affected by whatever is provoking aggression in this male, and the respective family thereby promises to deal with their own environmental matters.
Be as it may, on June 11, the males were barking and walking around their ranges.
However, I suspected that their behaviour was not that of the typical planning ahead and communicating.
Firstly, their vocalizations seemed different, perhaps less resonant as if the vocalizations were only partly based on the typical hormonal response.
It did not seem that these males had any aggression (that is apparently needed to be able to plan ahead) but that they were worried and even scared.
Two of the males were barking on neighbouring ranges, and they never approached one another, and they seemed to be inspecting very specific plots which were rather far from their range boundary.
I began wondering whether these males perhaps have suddenly realized that the fawn and the mother are gone.
The mother must have made the choice of moving the fawn mere hours before the male arrived, and perhaps there was no time for the paired females and the males to confer.
It is possible that the roe deer males are adapted to making long-term plans for their families/social groups while the females are more adept at taking swift, decisive actions (responding to current weather conditions rather than prevalent weather conditions which would also explain why males would take over during very cold weather because it might be unbearable for the females to still keep track of very minor and subtle changes when these changes are highly undelightful, i.e., it might be too stressful to be as observant to detail in weather fluctuations when the weather is pretty bad all of the time which is when the males with their ‘prevalent trend’ prognostications might step in).
I was under impression that these males were worried because they could not find their families but that they were also informing one another on the change in habitat use (as is polite).
Perhaps, in some families, where mature forests with their stable microclimate are not available, such drops in temperature would result in slight encroachment upon another family’s resources which then might be tolerated because they are temporary (perhaps when the fawn survives the cold spell, the mother leads the fawn back to the former habitat).
To me, it seemed that the two males were trying to locate their families and informing one another perhaps both on their family’s new locations but also on whether they had spotted the female+fawn units of the other male’s family.
It also seemed that the conversation had a calming effect on the males as they ceased trotting around and began pacing more slowly, perhaps initiating a more thorough, level-headed search.
If the mother is not around, it is possible that the fawn is not equipped to respond with any loud vocalizations and the soft squeals might not be sufficient to notify the anxious father of the fawn’s location (especially, if the fawns have been advised not to squeal at all unless the adult is very near).
One of the males was searching the only riparian forest which is located on its range and I cannot see where else the female would have taken the fawn but deeper into that forest.
The other male seemed to have returned from that direction (where there might be a range boundary) and perhaps he was trying to communicate that he had or had not seen the first male’s fawn near his range.
I would suspect that he had seen the fawn or otherwise sensed its presence (met the mother perhaps) because the first male appeared to calm down.
The other male was, meanwhile, localizing near an extensive growth of shrubs.
This family is not as fortunate because they have very little riparian forest which is very exposed (it should also be mentioned that winds were very high last night adding to the windchill factor).
The mother might have taken the fawn further inland to this grove which is not suitable for raising the fawn but which could ensure survival during such poor weather.
There was a third male whom I heard barking rather frantically but this male was located far from the other two males’ ranges (and it also happened at least an hour later).
This male’s family mostly lives in a highly disturbed habitat.
In fact, all three families that were exhibiting worry have the dominant proportion of their range comprised of suboptimal habitat (crops, private households etc.) and very scare availability of decent shelter the patches of which are widely scattered.
The male was barking and trotting near the smaller river where his family probably used to localize.
This male would have had the least contact with his family on daily basis because there is essentially no ‘pristine’ riparian habitat and he likely forages out in the open.
If the female had moved her fawn in this family, I cannot even begin to imagine where she led it to, and apparently neither could the male.
Having witnessed the nightly transition between mature forest and exposed grove habitats in the roe deer family which can be considered more fortunate in this area (although hardly they can be considered fortunate if we devised the perfect roe deer habitat or even an adequate roe deer habitat), I could not anticipate that other families might make more drastic decisions that would have such alarming consequences.
I hope all daddies found their mates and their babies before they could get seriously panicked.
The weather is, supposedly, bound to return to warmer temperatures by the end of the week, and the cold period itself cannot be that detrimental (apart from this extremely cold, chilly, damp, windy night) because it might slow down the vegetation ripening (becoming too fibrous to be truly nutritional).
Notes by Ieva 