Mute swans constitute the most common swan species in Latvia and, periodically, there had been pairs residing here and there on the river but, for the last few years, I had not observed any mute swans downstream from the town’s centre.
This pair, to my understanding, arrived in March already (if those are the same individuals) and they, at first, explored an artificial pond (not very large) near a small household.
I suppose they did not find the pond to their liking.
It has no shore vegetation cover (it was dug out only ca. 3 years ago and I am not certain whether the owners will allow for vegetation to establish) and the disturbance level is high.
While it is a small household, for some reason, they use a front of house lighting although the house is remote and there is absolutely no need to be wasting energy and annoying wildlife.
The illumination is very bright and it falls right on the pond surface.
Accordingly, I believe the swan couple is exploring the river habitat.
They do not seem to have established a nest site although egg laying is due or past. Or perhaps (hopefully, not) their eggs were lost, e.g., in the pond habitat.
The pair, nevertheless, keeps together.
My first observation was of them foraging in the river close to the less disturbed shore where humans almost never pass (at ca. 3 am).
It seems they had spent the entire night there because at ca. 5.30 am (that very same night) I saw them exactly in the same place where they were sleeping.
I was quite curious to observe them during daylight because I have this mute swan conundrum from my childhood what I hope to resolve through inspection of some old photographs for which reason I need to be able to tell mute swan males from females quite well in order to determine the sex of the individuals in the photographs (the individuals have not been photographed together but they can be seen in separate photos) (see Curious mute swan behaviour – observations from my childhood).
Therefore, I sneaked up on the pair although the area did not offer much opportunity for stealth.
The swans were, at the time, sleeping.
They had tucked their beaks under their wings (both swans had their necks inclined to the left which was the closest side to the shore by which they were resting – might be a note of importance) and they had located themselves right behind a small sandy ‘island’ (0.5 x 1 m) of riparian grassy vegetation (still sprouting).
Behind this island, they were protected from the current which is rather strong at the moment and which would otherwise have either washed them downstream or it would have forced them to move their legs in other to keep in place.
The female was the first to notice me, and she raised her head.
She swam slightly forth against the current and past the male (but not toward us – we were on the opposite elevated bank).
As she was swimming past, the male also raised his head, looked at us but then almost immediately tucked his head back under his wing.
It was quite adorable – it appeared the male was just overcome with sleepiness.
The female seemed to follow the male’s reactions very closely.
At this point, I began to suspect that the female was relying on the male’s opinion regarding either predation threat as such or perhaps disturbance by humans and their dogs, or perhaps disturbance further from their immediate location.
The following events suggested that the latter was the case because there was some rustling in the shrubs (the shrubline lies ca. 3 m from the water and there is a band of grassy vegetation between the shrubs and the river) on their shore.
To this rustling, the male did not react at all but the female (who seemed to have dismissed us as a potential trouble altogether) listened in carefully.
In fact, she paid much more attention to the rustling in the shrubs on her bank than she did to us (and we were about 5 m away right across the river).
As the rustling subsided, the female first tucked her head under the left wing and only then paddled to locate herself back behind the island and the male where she slept peacefully despite our continued presence.
These observations led me to several conclusions.
Firstly, the swan pair seems to be familiar with humans and dogs, and they were able to make assessment of the level of threat we posed, in particular.
Perhaps their risk evaluation was based on the distance (we were on the opposite shore), depth of river (it was one of the deepest spots and swans might have observed that humans are not very eager to swim across) but also some other cues that allowed them to identify us as low threat level individuals (e.g., I said some things to my dog and perhaps the swans could glean some signals from my voice which was soft and quiet and non-threatening if these swans have been exposed to a variety of human voices previously).
Secondly, it seemed to me that the female depended on the male’s judgement regarding us while the male trusted the female’s judgement regarding the rustling on their shore.
Perhaps they perceived the area as a sort of a nest site, and the female was then responsible over making risk assessments close to ‘nest’ (which she typically would during incubation, brooding etc.) while the male is responsible over risk evaluation further from the ‘nest’ (which he would while the female is incubating, brooding etc.).
Therefore, the male was relied upon regarding us (we were further away) while the female was relied upon regarding the rustling (which was perhaps about as far but on their side of the shore).
There could be other considerations, e.g., as humans and dogs are more often noticed from outside of the nest, males might be more experienced with these types of potential predators.
Meanwhile, the rustling on the other shore was quite clearly produced by some kind of an animal, and the female might have greater familiarity dealing with animals and also dealing with noises that are concealed by vegetation (as they would be near a nest vs. out in the open water where the male might be swimming more often).
I also found it curious that the male was staying close to the sandy island and he refused to move at all while the female located herself behind the male and she swam to and fro without much reserve.
Perhaps the male had taken the more difficult position where the stream is still rather strong, and the force of the current was then mitigated both by the island and the male before it reached the female.
This could have given the female an advantage while resting and maybe it was also physically easier for her to stir from the spot (to begin a swim and to return to the former resting site).
The male might have tried not to lose ground in his more precarious location which could have been why he did not respond to our arrival with a short swim the way the female did.
The swimming back downstream with her head tucked under the wing (also backwards – with her tail first) was quite adorable and whimsical but it could have offered some pragmatic benefits, as well (such as putting weight on the left side toward which she was steering and also slightly to the back which way she was swimming).
On April 29 (at about the same hour), we encountered this pair slightly upstream (a relatively wilder habitat with denser riparian forest on one side and a grove of trees on the other).
The pair had been foraging on the shore closer to us where there was some mud.
Unfortunately, I stumbled right upon them.
Typically, I avoid disturbing animals this way but I am not yet used to swans living there and in two out of three occasions described here I mistook them for the rather large ‘chunks’ of white foam which tends to aggregate on the shores (our river is polluted by several factories one of which produces soap among other similar products).
Thus, I simply believed it was the foam clinging to the shore.
The swans did not seem highly perturbed by us showing up even if we almost stepped on them.
They simply swam across the river whence they kept watching us somewhat curiously.
The female, once more, seemed to look to the male’s lead, and the male pushed his head under the water in a foraging motion.
This made wonder whether the male, both the morning before (when he was demonstratively slumbering on) and this morning, had perhaps tried to actively signal to the female (through tucking his head back under his wing or through pushing his head below water to forage) that he thought there was no threat.
Swans mate for life but this might be a new pair or maybe some behaviours that are characteristic to the nesting period are not observed as often by the other mate (because during this period the mates might be more separated in their activities).
It appeared to me that the male was trying to send a message to reassure the female and that they perhaps were yet learning to read one another’s subtle cues.
The pair foraged and swam leisurely along their shore and paid no further notice to us.
It was also interesting that on April 28 they seemed exhausted in the morning but on April 29 (during the same hour) they were sprightly and still intent on feeding.
If anything, Apr 28 was an extremely cold night.
It was not as cold temperature-wise as it was damp due to an extreme difference between day and night temperatures.
Perhaps the swans had exhausted themselves foraging and keeping warm.
They are also apparently not that familiar with the area because last night (when it was very cold) they were foraging in a cooler spot than this morning (in the ‘wilder’ section, the cold effect is not augmented by the surrounding open landscape but it is buffered by the riparian trees).
Tonight it was warmer and while there was mist over the river and over the open habitats, the period of cold was shorter and prior to the time the cold set in, it had been warmer, as well (yesterday was an exceptionally warm day, warmer than the day before).
I am not aware of what activities the swans had been engaging in last night and maybe they started out later or slept during the night etc.
It will be interesting to see what becomes of this couple if they do not nest, eventually, but also, of course, if they do nest.
Notes by Ieva 